Preface
Foreword
The Linux From Scratch Project has seen many changes in the few years of its existence. I personally became involved with the project in 1999, around the time of the 2.x releases. At that time, the build process was to create static binaries with the host system, then chroot and build the final binaries on top of the static ones. Later came the use of the /static directory to hold the initial static builds, keeping them separated from the final system, then the PureLFS process developed by Ryan Oliver and Greg Schafer, introducing a new toolchain build process that divorces even our initial builds from the host. Finally, LFS 6 bought Linux Kernel 2.6, the udev dynamic device structure, sanitized kernel headers, and other improvements to the Linux From Scratch system. The one "flaw" in LFS is that it has always been based on an x86 class processor. With the advent of the Athlon 64 and Intel EM64T processors, the x86-only LFS is no longer ideal. Throughout this time, Ryan Oliver developed and documented a process by which you could build Linux for any system and from any system, by use of cross-compilation techniques. Thus, the Cross-Compiled LFS (CLFS) was born. CLFS follows the same guiding principles the LFS project has always followed, e.g., knowing your system inside and out by virtue of having built the system yourself. Additionally, during a CLFS build, you will learn advanced techniques such as cross-build toolchains, multilib support (32 & 64-bit libraries side-by-side), alternative architectures such as Sparc, MIPS, and Alpha, and much more. We hope you enjoy building your own CLFS system, and the benefits that come from a system tailored to your needs. -Jeremy Utley, CLFS 1.x Release Manager (Page Author) Jim Gifford, CLFS Project Co-leader Ryan Oliver, CLFS Project Co-leader Joe Ciccone, Justin Knierim, Chris Staub, Matt Darcy, Ken Moffat, Manuel Canales Esparcia, and Nathan Coulson - CLFS Developers

Audience
There are many reasons why somebody would want to read this book. The principal reason is to install a Linux system from the source code. A question many people raise is, “why go through all the hassle of manually building a Linux system from scratch when you can just download and install an existing one?” That is a good question and is the impetus for this section of the book. One important reason for the existence of CLFS is to help people understand how a Linux system works. Building an CLFS system helps demonstrate what makes Linux tick, and how things work together and depend on each other. One of the best things this learning experience provides is the ability to customize Linux to your own tastes and needs. A key benefit of CLFS is that it allows users to have more control over their system without any reliance on a Linux implementation designed by someone else. With CLFS, you are in the driver's seat and dictate every aspect of the system, such as the directory layout and bootscript setup. You also dictate where, why, and how programs are installed. Another benefit of CLFS is the ability to create a very compact Linux system. When installing a regular distribution, one is often forced to include several programs which are probably never used. These programs waste disk space or CPU cycles. It is not difficult to build an CLFS system of less than 100 megabytes (MB), which is substantially viii

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 smaller than the majority of existing installations. Does this still sound like a lot of space? A few of us have been working on creating a very small embedded CLFS system. We successfully built a system that was specialized to run the Apache web server with approximately 8MB of disk space used. Further stripping could bring this down to 5 MB or less. Try that with a regular distribution! This is only one of the many benefits of designing your own Linux implementation. We could compare Linux distributions to a hamburger purchased at a fast-food restaurant—you have no idea what might be in what you are eating. CLFS, on the other hand, does not give you a hamburger. Rather, CLFS provides the recipe to make the exact hamburger desired. This allows users to review the recipe, omit unwanted ingredients, and add your own ingredients to enhance the flavor of the burger. When you are satisfied with the recipe, move on to preparing it. It can be made to exact specifications—broil it, bake it, deep-fry it, or barbecue it. Another analogy that we can use is that of comparing CLFS with a finished house. CLFS provides the skeletal plan of a house, but it is up to you to build it. CLFS maintains the freedom to adjust plans throughout the process, customizing it to the needs and preferences of the user. Security is an additional advantage of a custom built Linux system. By compiling the entire system from source code, you are empowered to audit everything and apply all the security patches desired. It is no longer necessary to wait for somebody else to compile binary packages that fix a security hole. Unless you examine the patch and implement it yourself, you have no guarantee that the new binary package was built correctly and adequately fixes the problem. The goal of Cross Linux From Scratch is to build a complete and usable foundation-level system. Readers who do not wish to build their own Linux system from scratch may not benefit from the information in this book. If you only want to know what happens while the computer boots, we recommend the “From Power Up To Bash Prompt” HOWTO located at http://axiom.anu.edu.au/~okeefe/p2b/ or on The Linux Documentation Project's (TLDP) website at http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html. The HOWTO builds a system which is similar to that of this book, but it focuses strictly on creating a system capable of booting to a BASH prompt. Consider your objective. If you wish to build a Linux system and learn along the way, this book is your best choice. There are too many good reasons to build your own CLFS system to list them all here. This section is only the tip of the iceberg. As you continue in your CLFS experience, you will find the power that information and knowledge truly bring.

Prerequisites
Building a CLFS system is not a simple task. It requires a certain level of existing knowledge of Unix system administration in order to resolve problems, and correctly execute the commands listed. In particular, as an absolute minimum, the reader should already have the ability to use the command line (shell) to copy or move files and directories, list directory and file contents, and change the current directory. It is also expected that the reader has a reasonable knowledge of using and installing Linux software. A basic knowledge of the architectures being used in the Cross LFS process and the host operating systems in use is also required. Because the CLFS book assumes at least this basic level of skill, the various CLFS support forums are unlikely to be able to provide you with much assistance. Your questions regarding such basic knowledge will likely go unanswered, or you will be referred to the CLFS essential pre-reading list. Before building a CLFS system, we recommend reading the following HOWTOs: • Software-Building-HOWTO ix

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 http://www.tldp.org/HOWTO/Software-Building-HOWTO.html This is a comprehensive guide to building and installing “generic” Unix software distributions under Linux. • The Linux Users' Guide http://www.linuxhq.com/guides/LUG/guide.html This guide covers the usage of assorted Linux software. • The Essential Pre-Reading Hint http://hints.cross-lfs.org/essential_prereading.txt This is a hint written specifically for users new to Linux. It includes a list of links to excellent sources of information on a wide range of topics. Anyone attempting to install CLFS should have an understanding of many of the topics in this hint.

Host System Requirements
You should be able to build a CLFS system from just about any Unix-type operating system. Your host system should have the following software with the minimum versions indicated. Also note that many distributions will place software headers into separate packages, often in the form of “[package-name]-devel” or “[package-name]-dev”. Be sure to install those if your distribution provides them. • • • • • • • • • • • • • • • • • • Bash-2.05a Binutils-2.12 (Versions greater than 2.18 are not recommended as they have not been tested) Bison-1.875 Bzip2-1.0.2 Coreutils-5.0 (or Sh-Utils-2.0, Textutils-2.0, and Fileutils-4.1) Diffutils-2.8 Findutils-4.1.20 Gawk-3.0 Gcc-2.95.3 (Versions greater than 4.2.4 are not recommended as they have not been tested) Glibc-2.2.5 (Versions greater than 2.7 are not recommended as they have not been tested) Grep-2.5 Gzip-1.2.4 Make-3.79.1 Ncurses-5.3 Patch-2.5.4 Sed-3.0.2 Tar-1.14 Texinfo-4.4

Typography
To make things easier to follow, there are a few typographical conventions used throughout this book. This section contains some examples of the typographical format found throughout Cross-Compiled Linux From Scratch. ./configure --prefix=/usr This form of text is designed to be typed exactly as seen unless otherwise noted in the surrounding text. It is also used in the explanation sections to identify which of the commands is being referenced. install-info: unknown option '--dir-file=/mnt/clfs/usr/info/dir' This form of text (fixed-width text) shows screen output, probably as the result of commands issued. This format is also used to show filenames, such as /etc/ld.so.conf. Emphasis This form of text is used for several purposes in the book. Its main purpose is to emphasize important points or items. http://cross-lfs.org/ xi

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 This format is used for hyperlinks, both within the CLFS community and to external pages. It includes HOWTOs, download locations, and websites. cat > ${CLFS}/etc/group << "EOF" root:x:0: bin:x:1: ...... EOF This format is used when creating configuration files. The first command tells the system to create the file ${CLFS}/etc/group from whatever is typed on the following lines until the sequence end of file (EOF) is encountered. Therefore, this entire section is generally typed as seen. [REPLACED TEXT] This format is used to encapsulate text that is not to be typed as seen or copied-and-pasted. passwd(5) This format is used to refer to a specific manual page (hereinafter referred to simply as a “man” page). The number inside parentheses indicates a specific section inside of man. For example, passwd has two man pages. Per CLFS installation instructions, those two man pages will be located at /usr/share/man/man1/passwd.1 and /usr/share/man/man5/passwd.5. Both man pages have different information in them. When the book uses passwd(5) it is specifically referring to /usr/share/man/man5/passwd.5. man passwd will print the first man page it finds that matches “passwd”, which will be /usr/share/man/man1/passwd.1. For this example, you will need to run man 5 passwd in order to read the specific page being referred to. It should be noted that most man pages do not have duplicate page names in different sections. Therefore, man [program name] is generally sufficient.

Structure
This book is divided into the following parts.

Part I - Introduction
Part I explains a few important notes on how to proceed with the Cross-LFS installation. This section also provides meta-information about the book.

Part II - Preparing for the Build
Part II describes how to prepare for the building process—making a partition and downloading the packages.

Part III - Make the Cross-Compile Tools
Part III shows you how to make a set of Cross-Compiler tools. These tools can run on your host system but allow you to build packages that will run on your target system.

Part IV - Building the Basic Tools
Part IV explains how to build a tool chain designed to operate on your target system. These are the tools that will allow you to build a working system on your target computer. xii

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Part V - Building the CLFS System
Part V guides the reader through the building of the CLFS system—compiling and installing all the packages one by one, setting up the boot scripts, and installing the kernel. The resulting Linux system is the foundation on which other software can be built to expand the system as desired. At the end of this book, there is an easy to use reference listing all of the programs, libraries, and important files that have been installed.

Appendices
The appendices contain information that doesn't really fit anywhere else in the book. Appendix A contains definitions of acronyms and terms used in the book; Appendix B gives acknowledgments to people who have helped work on the CLFS project and website; Appendix C and D have information about package dependencies and the the build order. Some architectures may have additional appendices for arch-specific issues.

Errata
The software used to create a CLFS system is constantly being updated and enhanced. Security warnings and bug fixes may become available after the CLFS book has been released. Some host systems may also have problems building CLFS. To check whether the package versions or instructions in this release of CLFS need any modifications to accommodate security vulnerabilities, other bug fixes, or host-specific issues, please visit http://trac.cross-lfs. org/clfs/errata/1.1.0/ before proceeding with your build. You should note any changes shown and apply them to the relevant section of the book as you progress with building the CLFS system.

1.2. How to Build a CLFS System
The CLFS system will be built by using a previously installed Unix system or Linux distribution (such as Debian, Fedora, Mandriva, SUSE, or Ubuntu). This existing system (the host) will be used as a starting point to provide necessary programs, including a compiler, linker, and shell, to build the new system. Select the “development” option during the distribution installation to be able to access these tools. As an alternative to installing an entire separate distribution onto your machine, you may wish to use the Linux From Scratch LiveCD. This CD works well as a host system, providing all the tools you need to successfully follow the instructions in this book. It does also contain source packages and patches for the LFS book, and a copy of the LFS book, but not the needed packages or book for CLFS. You can still use the CD for building CLFS, but you will need to download the packages, patches and book separately. You can also look at http://hints.cross-lfs. org/lfscd-remastering-howto.txt for infomation on building your own CD, replacing the LFS packages and book with those for CLFS. Once you have the CD, no network connection or additional downloads are necessary. For more information about the LFS LiveCD or to download a copy, visit http://www.linuxfromscratch.org/livecd/. Preparing a New Partition of this book describes how to create a new Linux native partition and file system, the place where the new CLFS system will be compiled and installed. Packages and Patches explains which packages and patches need to be downloaded to build a CLFS system and how to store them on the new file system. Final Preparations discusses the setup for an appropriate working environment. Please read Final Preparations carefully as it explains several important issues the developer should be aware of before beginning to work through Constructing Cross-Compile Tools and beyond. Constructing Cross-Compile Tools explains the installation of cross-compile tools which will be built on the host but be able to compile programs that run on the target machine. These cross-compile tools will be used to create a temporary, minimal system that will be the basis for building the final CLFS system. Some of these packages are needed to resolve circular dependencies—for example, to compile a compiler, you need a compiler. The process of building cross-compile tools first involves building and installing all the necessary tools to create a build system for the target machine. With these cross-compiled tools, we eliminate any dependencies on the toolchain from our host distro. After we build our “Cross-Tools”, we start building a very minimal working system in /tools. This minimal system will be built using the cross-toolchain in /cross-tools. In Installing Basic System Software, the full CLFS system is built. Depending on the system you are cross-compiling for, you will either boot the minimal temp-system on the target machine, or chroot into it. The chroot (change root) program is used to enter a virtual environment and start a new shell whose root directory will be set to the CLFS partition. This is very similar to rebooting and instructing the kernel to mount the CLFS partition as the root partition. The major advantage is that “chrooting” allows the builder to continue using the host while CLFS is being built. While waiting for package compilation to complete, a user can switch to a different virtual console (VC) or X desktop and continue using the computer as normal. Some systems cannot be built by chrooting so they must be booted instead. Generally, if you building for a different arch than the host system, you must reboot because the kernel will likely not support the target machine. Booting involves installing a few additional packages that are needed for bootup, installing bootscripts, and building a miminal kernel. We also describe some alternative booting methods in Section 7.18, “What to do next” To finish the installation, the CLFS-Bootscripts are set up in Setting Up System Bootscripts, and the kernel and boot loader are set up in Making the CLFS System Bootable. The End contains information on furthering the CLFS experience beyond this book. After the steps in this book have been implemented, the computer will be ready to reboot into the new CLFS system. 3

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 This is the process in a nutshell. Detailed information on each step is discussed in the following chapters and package descriptions. Items that may seem complicated will be clarified, and everything will fall into place as the reader embarks on the CLFS adventure.

1.3. Master Changelog
This is version 1.1.0 of the Cross-Compiled Linux From Scratch book, dated September 14, 2008. If this book is more than six months old, a newer and better version is probably already available. To find out, please check one of the mirrors via http://trac.cross-lfs.org/. Below is a list of detailed changes made since the previous release of the book.
Changelog Entries:

• September 13, 2008 • [jciccone] - Checked and updated all download locations. • September 7, 2008 • [jciccone] - A lot of text changes. • August 27, 2008 • [jciccone] - Add Texinfo to the list of Host System Requirements. • August 24, 2008 • [jciccone] - Update the paths to ld.so when configuring Glibc for each arch. • July 13, 2008 • [jciccone] - Add a page right before Entering the Chroot Enviornment. This page covers the problem of building a 32bit system from a 64bit host or building a older 32bit system from another newer 32bit system. • July 12, 2008 • [jciccone] - Drop the minix tools from the chroot Util-Linux-NG build. • July 11, 2008 • [ken] - Add a patch to address known perl vulnerabilities. • July 7, 2008 • [jciccone] - Change the command that creates the clfs user to not include -k /dev/null. Newer versions of Shadow (4.1.2) apparently any argument passed to -k to be a directory. • July 7, 2008 • [jciccone] - Fix a omission in the Udev lib64 patch. Thanks to AcidPoison for catching this and reporting it in Trac. • July 6, 2008 • [jciccone] - Now that shadow doesn't provide any libraries we only need to build it once on multilib. • June 28, 2008 • [jciccone] - Downgraded the Vim Branch Update patch back to -2 from -3. • [jciccone] - Remove the commands that relocate the Shadow libraries as they are not provided in newer versions of shadow. Also only build 64bit, since there are no libraries anymore. • [jciccone] - Link /tools/bin/echo to /bin/echo foe one of the Glibc tests. 4

1.4. Changelog for x86
Below is a list of changes specifics for this architecture made since the previous release of the book. For general changes see Master Changelog,
Changelog Entries:

• July 08, 2008 • [jciccone] - Added the 256-Byte Inode patch to Grub. • March 18, 2008 • [jciccone] - Fixed the Glibc i586_chk patch and updated it to -2. • August 28, 2006 • [jim] - Changelog restarted, see the 1.0.0 book for the old changelog.

1.5. Resources
1.5.1. FAQ
If during the building of the CLFS system you encounter any errors, have any questions, or think there is a typo in the book, please start by consulting the Frequently Asked Questions (FAQ) that is located at http://trac.cross-lfs. org/wiki/faq.

1.5.2. Mailing Lists
The cross-lfs.org server hosts a number of mailing lists used for the development of the CLFS project. These lists include the main development and support lists, among others. If the FAQ does not contain your answer, you can search the CLFS lists via The Mail Archive http://www.mail-archive.com. You can find the mail lists with the following link: http://www.mail-archive.com/index.php?hunt=clfs For information on the different lists, how to subscribe, archive locations, and additional information, visit http://trac. cross-lfs.org/wiki/lists.

1.5.3. News Server
Cross-LFS does not maintain it's own News Server, but we do provide access via gmane.org http://gmane.org. If you want to subscribe to the Cross-LFS via a newsreader you can utilize gmane.org. You can find the game search for CLFS with the following link: http://dir.gmane.org/search.php?match=clfs

1.5.4. IRC
Several members of the CLFS community offer assistance on our community Internet Relay Chat (IRC) network. Before using this support, please make sure that your question is not already answered in the CLFS FAQ or the mailing list archives. You can find the IRC network at chat.freenode.net. The support channel for cross-lfs is named #cross-lfs. If you need to show people the output of your problems, please use http://pastebin.cross-lfs.org and reference the pastebin URL when asking your questions. 16

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1.5.5. Mirror Sites
The CLFS project has a number of world-wide mirrors to make accessing the website and downloading the required packages more convenient. Please visit the CLFS website at http://trac.cross-lfs.org/wiki/mirrors for mirrors of CLFS.

1.6. Help
If an issue or a question is encountered while working through this book, check the FAQ page at http://trac.cross-lfs. org/wiki/faq#generalfaq. Questions are often already answered there. If your question is not answered on this page, try to find the source of the problem. The following hint will give you some guidance for troubleshooting: http://hints. cross-lfs.org/errors.txt. We also have a wonderful CLFS community that is willing to offer assistance through the mailing lists and IRC (see the Section 1.5, “Resources” section of this book). However, we get several support questions everyday and many of them can be easily answered by going to the FAQ and by searching the mailing lists first. So for us to offer the best assistance possible, you need to do some research on your own first. This allows us to focus on the more unusual support needs. If your searches do not produce a solution, please include all relevant information (mentioned below) in your request for help.

1.6.1. Things to Mention
Apart from a brief explanation of the problem being experienced, the essential things to include in any request for help are: • • • • • • The version of the book being used (in this case 1.1.0) The host distribution and version being used to create CLFS. The architecture of the host and target. The value of the $CLFS_HOST, $CLFS_TARGET, $BUILD32, and $BUILD64 environment variables. The package or section in which the problem was encountered. The exact error message or symptom received. See Section 1.6.3, “Compilation Problems” below for an example. • Note whether you have deviated from the book at all. A package version change or even a minor change to any command is considered deviation.

Note
Deviating from this book does not mean that we will not help you. After all, the CLFS project is about personal preference. Be upfront about any changes to the established procedure—this helps us evaluate and determine possible causes of your problem.

1.6.2. Configure Script Problems
If something goes wrong while running the configure script, review the config.log file. This file may contain the errors you encountered during configure. It often logs errors that may have not been printed to the screen. Include only the relevant lines if you need to ask for help. 17

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1.6.3. Compilation Problems
Both the screen output and the contents of various files are useful in determining the cause of compilation problems. The screen output from the configure script and the make run can be helpful. It is not necessary to include the entire output, but do include enough of the relevant information. Below is an example of the type of information to include from the screen output from make: gcc -DALIASPATH=\"/mnt/clfs/usr/share/locale:.\" -DLOCALEDIR=\"/mnt/clfs/usr/share/locale\" -DLIBDIR=\"/mnt/clfs/usr/lib\" -DINCLUDEDIR=\"/mnt/clfs/usr/include\" -DHAVE_CONFIG_H -I. -I. -g -O2 -c getopt1.c gcc -g -O2 -static -o make ar.o arscan.o commands.o dir.o expand.o file.o function.o getopt.o implicit.o job.o main.o misc.o read.o remake.o rule.o signame.o variable.o vpath.o default.o remote-stub.o version.o opt1.o -lutil job.o: In function `load_too_high': /clfs/tmp/make-3.79.1/job.c:1565: undefined reference to `getloadavg' collect2: ld returned 1 exit status make[2]: *** [make] Error 1 make[2]: Leaving directory `/clfs/tmp/make-3.79.1' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/clfs/tmp/make-3.79.1' make: *** [all-recursive-am] Error 2 In this case, many people would just include the bottom section: make [2]: *** [make] Error 1 This is not enough information to properly diagnose the problem because it only notes that something went wrong, not what went wrong. The entire section, as in the example above, is what should be saved because it includes the command that was executed and the associated error message(s). An excellent article about asking for help on the Internet is available online at http://catb. org/~esr/faqs/smart-questions.html. Read and follow the hints in this document to increase the likelihood of getting the help you need.

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Part II. Preparing for the Build

Cross-Compiled Linux From Scratch - Version 1.1.0-x86

Chapter 2. Preparing a New Partition
2.1. Introduction
In this chapter, the partition which will host the CLFS system is prepared. We will create the partition itself, create a file system on it, and mount it.

2.2. Creating a New Partition
Like most other operating systems, CLFS is usually installed on a dedicated partition. The recommended approach to building a CLFS system is to use an available empty partition or, if you have enough unpartitioned space, to create one. However, if your building for a different architecture you can simply build everything in “/mnt/clfs” and transfer it to your target machine. A minimal system requires around 2.5 gigabytes (GB). This is enough to store all the source tarballs and compile the packages. The CLFS system itself will not take up this much room. A large portion of this requirement is to provide sufficient free temporary storage. Compiling packages can require a lot of disk space which will be reclaimed after the package is installed. If the CLFS system is intended to be the primary Linux system, additional software will probably be installed which will require additional space (2-10 GB). Because there is not always enough Random Access Memory (RAM) available for compilation processes, it is a good idea to use a small disk partition as swap space. This is used by the kernel to store seldom-used data and leave more memory available for active processes. The swap partition for an CLFS system can be the same as the one used by the host system, in which case it is not necessary to create another one. Start a disk partitioning program such as cfdisk or fdisk with a command line option naming the hard disk on which the new partition will be created—for example /dev/hda for the primary Integrated Drive Electronics (IDE) disk. Create a Linux native partition and a swap partition, if needed. Please refer to cfdisk(8) or fdisk(8) if you do not yet know how to use the programs. Remember the designation of the new partition (e.g., hda5). This book will refer to this as the CLFS partition. Also remember the designation of the swap partition. These names will be needed later for the /etc/fstab file.

2.3. Creating a File System on the Partition
Now that a blank partition has been set up, the file system can be created. The most widely-used system in the Linux world is the second extended file system (ext2), but with newer high-capacity hard disks, journaling file systems are becoming increasingly popular. We will create an ext2 file system. Instructions for other file systems can be found at http://cblfs.cross-lfs.org/index.php?section=6#File_System_.2F_Block_Device_.2F_Inode_Management_Tools. To create an ext2 file system on the CLFS partition, run the following: mke2fs /dev/[xxx] Replace [xxx] with the name of the CLFS partition (hda5 in our previous example).

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Note
Some host distributions use custom features in their filesystem creation tools (E2fsprogs). This can cause problems when booting into your new CLFS system, as those features will not be supported by the CLFS-installed E2fsprogs; you will get an error similar to unsupported filesystem features, upgrade your e2fsprogs. To check if your host system uses custom enhancements, run the following command: debugfs -R feature /dev/[xxx] If the output contains features other than: dir_index; filetype; large_file; resize_inode or sparse_super then your host system may have custom enhancements. In that case, to avoid later problems, you should compile the stock E2fsprogs package and use the resulting binaries to re-create the filesystem on your CLFS partition: cd /tmp tar xjf /path/to/sources/e2fsprogs-1.40.4.tar.bz2 cd e2fsprogs-1.40.4 mkdir build cd build ../configure make #note that we intentionally don't 'make install' here! ./misc/mke2fs /dev/[xxx] cd /tmp rm -rf e2fsprogs-1.40.4 If a swap partition was created, it will need to be initialized for use by issuing the command below. If you are using an existing swap partition, there is no need to format it. mkswap /dev/[yyy] Replace [yyy] with the name of the swap partition.

2.4. Mounting the New Partition
Now that a file system has been created, the partition needs to be made accessible. In order to do this, the partition needs to be mounted at a chosen mount point. For the purposes of this book, it is assumed that the file system is mounted under /mnt/clfs, but the directory choice is up to you. Choose a mount point and assign it to the CLFS environment variable by running: export CLFS=/mnt/clfs Next, create the mount point and mount the CLFS file system by running: mkdir -pv ${CLFS} mount -v /dev/[xxx] ${CLFS} Replace [xxx] with the designation of the CLFS partition. 21

Replace [xxx] and [yyy] with the appropriate partition names. Ensure that this new partition is not mounted with permissions that are too restrictive (such as the nosuid, nodev, or noatime options). Run the mount command without any parameters to see what options are set for the mounted CLFS partition. If nosuid, nodev, and/or noatime are set, the partition will need to be remounted. Now that there is an established place to work, it is time to download the packages.

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Chapter 3. Packages and Patches
3.1. Introduction
This chapter includes a list of packages that need to be downloaded for building a basic Linux system. The listed version numbers correspond to versions of the software that are known to work, and this book is based on their use. We highly recommend not using newer versions because the build commands for one version may not work with a newer version. The newest package versions may also have problems that require work-arounds. These work-arounds will be developed and stabilized in the development version of the book. Download locations may not always be accessible. If a download location has changed since this book was published, Google (http://www.google.com/) provides a useful search engine for most packages. If this search is unsuccessful, try one of the alternative means of downloading discussed at http://cross-lfs.org/files/packages/1.1.0/. Create a directory called ${CLFS}/sources and use it to store your sources and patches. All packages should be compiled there as well. Using any other location for compiling may have unexpected results. To create this directory, execute, as user root, the following command before starting the download session: mkdir -v ${CLFS}/sources Make this directory writable and sticky. When a directory is marked “sticky”, that means that even if multiple users have write permission on that directory, any file within that directory can only be deleted or modified by its owner. The following command will enable the write and sticky modes: chmod -v a+wt ${CLFS}/sources

Note
File (4.23) may no longer be available at the listed location. The site administrators of the master download location occasionally remove older versions when new ones are released. An alternative download location that may have the correct version available is http://cross-lfs.org/files/packages/1.1.0/. 24

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Total size of these patches: about 8 MB In addition to the above required patches, there exist a number of optional patches created by the CLFS community. These optional patches solve minor problems or enable functionality that is not enabled by default. Feel free to peruse the patches database located at http://patches.cross-lfs.org/1.1.0/ and acquire any additional patches to suit the system needs.

Chapter 4. Final Preparations
4.1. About ${CLFS}
Throughout this book, the environment variable CLFS will be used several times. It is paramount that this variable is always defined. It should be set to the mount point chosen for the CLFS partition. Check that the CLFS variable is set up properly with: echo ${CLFS} Make sure the output shows the path to the CLFS partition's mount point, which is /mnt/clfs if the provided example was followed. If the output is incorrect, the variable can be set with: export CLFS=/mnt/clfs Having this variable set is beneficial in that commands such as install -dv ${CLFS}/tools can be typed literally. The shell will automatically replace “${CLFS}” with “/mnt/clfs” (or whatever the variable was set to) when it processes the command line. If you haven't created the ${CLFS} directory, do so at this time by issuing the following commands: install -dv ${CLFS} Do not forget to check that ${CLFS} is set whenever you leave and reenter the current working environment (as when doing a “su” to root or another user).

4.2. Creating the ${CLFS}/tools Directory
All programs compiled in Constructing a Temporary System will be installed under ${CLFS}/tools to keep them separate from the programs compiled in Installing Basic System Software. The programs compiled here are temporary tools and will not be a part of the final CLFS system. By keeping these programs in a separate directory, they can easily be discarded later after their use. This also prevents these programs from ending up in the host production directories (easy to do by accident in Constructing a Temporary System). Create the required directory by running the following as root: install -dv ${CLFS}/tools The next step is to create a /tools symlink on the host system. This will point to the newly-created directory on the CLFS partition. Run this command as root as well: ln -sv ${CLFS}/tools /

Note
The above command is correct. The ln command has a few syntactic variations, so be sure to check info coreutils ln and ln(1) before reporting what you may think is an error. The created symlink enables the toolchain to be compiled so that it always refers to /tools, meaning that the compiler, assembler, and linker will work. This will provide a common place for our temporary tools system. 32

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4.3. Creating the ${CLFS}/cross-tools Directory
The cross-binutils and cross-compiler built in Constructing Cross-Compile Tools will be installed under ${CLFS}/cross-tools to keep them separate from the host programs. The programs compiled here are cross-tools and will not be a part of the final CLFS system or the temp-system. By keeping these programs in a separate directory, they can easily be discarded later after their use. Create the required directory by running the following as root: install -dv ${CLFS}/cross-tools The next step is to create a /cross-tools symlink on the host system. This will point to the newly-created directory on the CLFS partition. Run this command as root as well: ln -sv ${CLFS}/cross-tools / The symlink isn't technically necessary (though the book's instructions do assume its existence), but is there mainly for consistency (because /tools is also symlinked to ${CLFS}/tools) and to simplify the installation of the cross-compile tools.

4.4. Adding the CLFS User
When logged in as user root, making a single mistake can damage or destroy a system. Therefore, we recommend building the packages as an unprivileged user. You could use your own user name, but to make it easier to set up a clean work environment, create a new user called clfs as a member of a new group (also named clfs) and use this user during the installation process. As root, issue the following commands to add the new user: groupadd clfs useradd -s /bin/bash -g clfs -d /home/clfs clfs mkdir -pv /home/clfs chown -v clfs:clfs /home/clfs
The meaning of the command line options:

-s /bin/bash This makes bash the default shell for user clfs. -g clfs This option adds user clfs to group clfs. clfs This is the actual name for the created group and user. To log in as clfs (as opposed to switching to user clfs when logged in as root, which does not require the clfs user to have a password), give clfs a password: passwd clfs Grant clfs full access to ${CLFS}/cross-tools and ${CLFS}/tools by making clfs the directorys' owner: chown -v clfs ${CLFS}/tools chown -v clfs ${CLFS}/cross-tools 33

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 If a separate working directory was created as suggested, give user clfs ownership of this directory: chown -v clfs ${CLFS}/sources Next, login as user clfs. This can be done via a virtual console, through a display manager, or with the following substitute user command: su - clfs The “-” instructs su to start a login shell as opposed to a non-login shell. The difference between these two types of shells can be found in detail in bash(1) and info bash.

4.5. Setting Up the Environment
Set up a good working environment by creating two new startup files for the bash shell. While logged in as user clfs, issue the following command to create a new .bash_profile: cat > ~/.bash_profile << "EOF" exec env -i HOME=${HOME} TERM=${TERM} PS1='\u:\w\$ ' /bin/bash EOF When logged on as user clfs, the initial shell is usually a login shell which reads the /etc/profile of the host (probably containing some settings and environment variables) and then .bash_profile. The exec env -i.../bin/bash command in the .bash_profile file replaces the running shell with a new one with a completely empty environment, except for the HOME, TERM, and PS1 variables. This ensures that no unwanted and potentially hazardous environment variables from the host system leak into the build environment. The technique used here achieves the goal of ensuring a clean environment. The new instance of the shell is a non-login shell, which does not read the /etc/profile or .bash_profile files, but rather reads the .bashrc file instead. Create the .bashrc file now: cat > ~/.bashrc << "EOF" set +h umask 022 CLFS=/mnt/clfs LC_ALL=POSIX PATH=/cross-tools/bin:/bin:/usr/bin export CLFS LC_ALL PATH EOF The set +h command turns off bash's hash function. Hashing is ordinarily a useful feature—bash uses a hash table to remember the full path of executable files to avoid searching the PATH time and again to find the same executable. However, the new tools should be used as soon as they are installed. By switching off the hash function, the shell will always search the PATH when a program is to be run. As such, the shell will find the newly compiled tools in /cross-tools as soon as they are available without remembering a previous version of the same program in a different location. Setting the user file-creation mask (umask) to 022 ensures that newly created files and directories are only writable by their owner, but are readable and executable by anyone (assuming default modes are used by the open(2) system call, new files will end up with permission mode 644 and directories with mode 755). The CLFS variable should be set to the chosen mount point. 34

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 The LC_ALL variable controls the localization of certain programs, making their messages follow the conventions of a specified country. If the host system uses a version of Glibc older than 2.2.4, having LC_ALL set to something other than “POSIX” or “C” (during this chapter) may cause issues if you exit the chroot environment and wish to return later. Setting LC_ALL to “POSIX” or “C” (the two are equivalent) ensures that everything will work as expected in the chroot environment. By putting /cross-tools/bin at the beginning of the PATH, the cross-compiler built in Constructing Cross-Compile Tools will be picked up by the build process for the temp-system packages before anything that may be installed on the host. This, combined with turning off hashing, helps to ensure that you will be using the cross-compile tools to build the temp-system in /tools. Finally, to have the environment fully prepared for building the temporary tools, source the just-created user profile: source ~/.bash_profile

4.6. About the Test Suites
Most packages provide a test suite. Running the test suite for a newly built package is a good idea because it can provide a “sanity check” indicating that everything compiled correctly. A test suite that passes its set of checks usually proves that the package is functioning as the developer intended. It does not, however, guarantee that the package is totally bug free. It is not possible to run testsuites when cross-compiling, so package installation instructions do not explain how to run testsuites until Installing Basic System Software.

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Part III. Make the Cross-Compile Tools

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Chapter 5. Constructing Cross-Compile Tools
5.1. Introduction
This chapter shows you how to create cross platform tools. If for some reason you have to stop and come back later, remember to use the su - clfs command, and it will setup the build environment that you left.

5.1.1. Common Notes
Important
Before issuing the build instructions for a package, the package should be unpacked as user clfs, and a cd into the created directory should be performed. The build instructions assume that the bash shell is in use. Several of the packages are patched before compilation, but only when the patch is needed to circumvent a problem. A patch is often needed in both this and the next chapters, but sometimes in only one or the other. Therefore, do not be concerned if instructions for a downloaded patch seem to be missing. Warning messages about offset or fuzz may also be encountered when applying a patch. Do not worry about these warnings, as the patch was still successfully applied. During the compilation of most packages, there will be several warnings that scroll by on the screen. These are normal and can safely be ignored. These warnings are as they appear—warnings about deprecated, but not invalid, use of the C or C++ syntax. C standards change fairly often, and some packages still use the older standard. This is not a problem, but does prompt the warning.

Important
After installing each package, both in this and the next chapters, delete its source and build directories, unless specifically instructed otherwise. Deleting the sources prevents mis-configuration when the same package is reinstalled later.

5.2. Build CFLAGS
CFLAGS and CXXFLAGS must not be set during the building of cross-tools. To disable CFLAGS and CXXFLAGS use the following commands: unset CFLAGS unset CXXFLAGS Now add these to ~/.bashrc, just in case you have to exit and restart building later: echo unset CFLAGS >> ~/.bashrc echo unset CXXFLAGS >> ~/.bashrc

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5.3. Build Variables
Setting Host and Target

During the building of the cross-compile tools you will need to set a few variables that will be dependent on your particular needs. The first variable will be the triplet of the host machine, which will be put into the CLFS_HOST variable. To account for the possibility that the host and target are the same arch, as cross-compiling won't work when host and target are the same, part of the triplet needs to be changed slightly to add "cross". Set CLFS_HOST using the following command: export CLFS_HOST="$(echo $MACHTYPE | \ sed "s/$(echo $MACHTYPE | cut -d- -f2)/cross/")" Now you will need to set the triplet for the target architecture. Set the target variable using the following command: export CLFS_TARGET="[target triplet]" Replace [target triplet] with the appropriate machine triplet using the table at the bottom of the page.
Copy settings to the Environment

Now add these to ~/.bashrc, just in case you have to exit and restart building later: echo export CLFS_HOST=\""${CLFS_HOST}\"" >> ~/.bashrc echo export CLFS_TARGET=\""${CLFS_TARGET}\"" >> ~/.bashrc
Table 5.1. Processor Type and Target Triplets

5.4.1. Installation of Linux-Headers
For this step you will need the kernel tarballs. Install the header files that are common to all architectures: install -dv /tools/include make mrproper make ARCH=i386 headers_check make ARCH=i386 INSTALL_HDR_PATH=dest headers_install cp -rv dest/include/* /tools/include Details on this package are located in Section 10.5.2, “Contents of Linux-Headers.”

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5.5. File-4.23
The File package contains a utility for determining the type of a given file or files.

5.5.1. Installation of File
Prepare File for compilation: ./configure --prefix=/cross-tools Compile the package: make Install the package: make install Details on this package are located in Section 10.30.2, “Contents of File.”

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5.6. Cross Binutils-2.18
The Binutils package contains a linker, an assembler, and other tools for handling object files.

5.6.1. Installation of Cross Binutils
It is important that Binutils be compiled before Glibc and GCC because both Glibc and GCC perform various tests on the available linker and assembler to determine which of their own features to enable. To make sure that the proper syntax is used for a couple of tools, apply the following patch: patch -Np1 -i ../binutils-2.18-posix-1.patch The following patches merges all updates from the 2.18 Branch from the Binutils developers: patch -Np1 -i ../binutils-2.18-branch_update-3.patch The Binutils documentation recommends building Binutils outside of the source directory in a dedicated build directory: mkdir -v ../binutils-build cd ../binutils-build Prepare Binutils for compilation: AR=ar AS=as ../binutils-2.18/configure --prefix=/cross-tools \ --host=${CLFS_HOST} --target=${CLFS_TARGET} --with-lib-path=/tools/lib \ --disable-nls --enable-shared --disable-multilib
The meaning of the configure options:

--prefix=/cross-tools This tells the configure script to prepare to install the package in the /cross-tools directory. --host=${CLFS_HOST} When used with --target, this creates a cross-architecture executable that creates files for ${CLFS_TARGET} but runs on ${CLFS_HOST}. --target=${CLFS_TARGET} When used with --host, this creates a cross-architecture executable that creates files for ${CLFS_TARGET} but runs on ${CLFS_HOST}. --with-lib-path=/tools/lib This tells the configure script to specify the library search path during the compilation of Binutils, resulting in /tools/lib being passed to the linker. This prevents the linker from searching through library directories on the host. --disable-nls This disables internationalization as i18n is not needed for the cross-compile tools. --enable-shared Enable the creation of the shared libraries. --disable-multilib This option disables the building of a multilib capable Binutils. 41

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Compile the package: make configure-host make
The meaning of the make options:

configure-host This checks the host environment and makes sure all the necessary tools are available to compile Binutils. Install the package: make install Copy libiberty.h to /tools/include directory: cp -v ../binutils-2.18/include/libiberty.h /tools/include Details on this package are located in Section 10.9.2, “Contents of Binutils.”

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5.7. Cross GCC-4.2.4 - Static
The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.

--with-local-prefix=/tools The purpose of this switch is to remove /usr/local/include from gcc's include search path. This is not absolutely essential, however, it helps to minimize the influence of the host system. --disable-shared Disables the creation of the shared libraries. --disable-threads This will prevent GCC from looking for the multi-thread include files, since they haven't been created for this architecture yet. GCC will be able to find the multi-thread information after the Glibc headers are created. 43

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 --enable-languages=c This option ensures that only the C compiler is built. Continue with compiling the package: make all-gcc Install the package: make install-gcc Details on this package are located in Section 10.10.2, “Contents of GCC.”

5.8.1. Installation of Glibc
It should be noted that compiling Glibc in any way other than the method suggested in this book puts the stability of the system at risk. Disable linking to libgcc_eh: patch -Np1 -i ../glibc-2.7-libgcc_eh-1.patch The following patch fixes an issue that can cause localdef to segfault: patch -Np1 -i ../glibc-2.7-localedef_segfault-1.patch The following patch ensures that memcpy_chk, mempcpy_chk, and memset_chk are defined for i586. patch -Np1 -i ../glibc-2.7-i586_chk-2.patch The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory: mkdir -v ../glibc-build cd ../glibc-build The following lines need to be added to config.cache for Glibc to support NPTL: echo "libc_cv_forced_unwind=yes" > config.cache echo "libc_cv_c_cleanup=yes" >> config.cache Prepare Glibc for compilation: BUILD_CC="gcc" CC="${CLFS_TARGET}-gcc" \ AR="${CLFS_TARGET}-ar" RANLIB="${CLFS_TARGET}-ranlib" \ CFLAGS="-march=$(cut -d- -f1 <<< $CLFS_TARGET) -mtune=generic -g -O2" \ ../glibc-2.7/configure --prefix=/tools \ --host=${CLFS_TARGET} --build=${CLFS_HOST} \ --disable-profile --enable-add-ons \ --with-tls --enable-kernel=2.6.0 --with-__thread \ --with-binutils=/cross-tools/bin --with-headers=/tools/include \ --cache-file=config.cache
The meaning of the new configure options:

BUILD_CC="gcc" This sets Glibc to use the current compiler on our system. This is used to create the tools Glibc uses during its build. CC="${CLFS_TARGET}-gcc" This forces Glibc to use the GCC compiler that we made for our target architecture. 45

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 AR="${CLFS_TARGET}-ar" This forces Glibc to use the ar utility we made for our target architecture. RANLIB="${CLFS_TARGET}-ranlib" This forces Glibc to use the ranlib utility we made for our target architecture. CFLAGS="-march=$(cut -d- -f1 <<< $CLFS_TARGET) -mtune=generic -g -O2" Forces Glibc to optimize for our target system. --disable-profile This builds the libraries without profiling information. Omit this option if profiling on the temporary tools is necessary. --enable-add-ons This tells Glibc to utilize all add-ons that are available. --with-tls This tells Glibc to use Thread Local Storage. --enable-kernel=2.6.0 This tells Glibc to compile the library with support for 2.6.x Linux kernels. --with-__thread This tells Glibc to use use the __thread for libc and libpthread builds. --with-binutils=/cross-tools/bin This tells Glibc to use the Binutils that are specific to our target architecture. --with-headers=/tools/include This tells Glibc to compile itself against the headers recently installed to the /tools directory, so that it knows exactly what features the kernel has and can optimize itself accordingly. --cache-file=config.cache This tells Glibc to utilize a premade cache file. During this stage the following warning might appear: configure: WARNING: *** These auxiliary programs are missing or *** incompatible versions: msgfmt *** some features will be disabled. *** Check the INSTALL file for required versions. The missing or incompatible msgfmt program is generally harmless. This msgfmt program is part of the Gettext package which the host distribution should provide. Compile the package: make Install the package: make install Details on this package are located in Section 10.7.5, “Contents of Glibc.”

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5.9. Cross GCC-4.2.4 - Final
The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.

Cross-Compiled Linux From Scratch - Version 1.1.0-x86
The meaning of the new configure options:

--enable-languages=c,c++ This option ensures that only the C and C++ compilers are built. --enable-__cxa_atexit This option allows use of __cxa_atexit, rather than atexit, to register C++ destructors for local statics and global objects and is essential for fully standards-compliant handling of destructors. It also affects the C++ ABI and therefore results in C++ shared libraries and C++ programs that are interoperable with other Linux distributions. --enable-c99 Enable C99 support for C programs. --enable-long-long Enables long long support in the compiler. --enable-threads=posix This enables C++ exception handling for multi-threaded code. Continue with compiling the package: make AS_FOR_TARGET="${CLFS_TARGET}-as" \ LD_FOR_TARGET="${CLFS_TARGET}-ld" Install the package: make install Details on this package are located in Section 10.10.2, “Contents of GCC.”

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Part IV. Building the Basic Tools

Cross-Compiled Linux From Scratch - Version 1.1.0-x86

Chapter 6. Constructing a Temporary System
6.1. Introduction
This chapter shows how to compile and install a minimal Linux system. This system will contain just enough tools to start constructing the final CLFS system in Installing Basic System Software and allow a working environment with more user convenience than a minimum environment would. The tools in this chapter are cross-compiled using the toolchain in /cross-tools and will be installed under the ${CLFS}/tools directory to keep them separate from the files installed in Installing Basic System Software and the host production directories. Since the packages compiled here are temporary, we do not want them to pollute the soon-to-be CLFS system. Check one last time that the CLFS environment variable is set up properly: echo ${CLFS} Make sure the output shows the path to the CLFS partition's mount point, which is /mnt/clfs, using our example. During this section of the build you will see several WARNING messages like the one below. It is safe to ignore these messages. configure: WARNING: If you wanted to set the --build type, don't use --host. If a cross compiler is detected then cross compile mode will be used.

6.3. Binutils-2.18
The Binutils package contains a linker, an assembler, and other tools for handling object files.

6.3.1. Installation of Binutils
To make sure that the proper syntax is used for a couple of tools, apply the following patch: patch -Np1 -i ../binutils-2.18-posix-1.patch The following patches merges all updates from the 2.18 Branch from the Binutils developers: patch -Np1 -i ../binutils-2.18-branch_update-3.patch The Binutils documentation recommends building Binutils outside of the source directory in a dedicated build directory: mkdir -v ../binutils-build cd ../binutils-build Prepare Binutils for compilation: ../binutils-2.18/configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} --target=${CLFS_TARGET} \ --disable-nls --enable-shared --disable-multilib Compile the package: make configure-host make Install the package: make install Details on this package are located in Section 10.9.2, “Contents of Binutils.”

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6.4. GCC-4.2.4
The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.

6.4.1. Installation of GCC
The following patch enables fixes compilation errors with the kernel: patch -Np1 -i ../gcc-4.2.4-PR31490-1.patch Make a couple of essential adjustments to the specs file to ensure GCC uses our build environment: patch -Np1 -i ../gcc-4.2.4-specs-1.patch To make sure that a couple of tools use the proper syntax, apply the following patch: patch -Np1 -i ../gcc-4.2.4-posix-1.patch The following patch ensures that gcc does not search the /usr directory for libgcc_s.so when cross-compiling: patch -Np1 -i ../gcc-4.2.4-cross_search_paths-1.patch Now we will change cpp's search path so it won't look in /usr/include: cp -v gcc/cppdefault.c{,.orig} sed -e '/#define STANDARD_INCLUDE_DIR/s@"/usr/include"@0@g' \ gcc/cppdefault.c.orig > gcc/cppdefault.c Also, we need to set the directory searched by the fixincludes process for system headers, so it won't look at the host's headers: cp -v gcc/Makefile.in{,.orig} sed -e 's@\(^NATIVE_SYSTEM_HEADER_DIR =\).*@\1 /tools/include@g' \ gcc/Makefile.in.orig > gcc/Makefile.in The GCC documentation recommends building GCC outside of the source directory in a dedicated build directory: mkdir -v ../gcc-build cd ../gcc-build Before starting to build GCC, remember to unset any environment variables that override the default optimization flags. Prepare GCC for compilation: ../gcc-4.2.4/configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} --target=${CLFS_TARGET} \ --with-local-prefix=/tools --enable-long-long --enable-c99 \ --enable-shared --enable-threads=posix --enable-__cxa_atexit \ --disable-nls --enable-languages=c,c++ --disable-libstdcxx-pch
The meaning of the new configure options:

--disable-libstdcxx-pch Do not build the pre-compiled header (PCH) for libstdc++. It takes up a lot of space, and we have no use for it. 52

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Compile the package: make AS_FOR_TARGET="${AS}" \ LD_FOR_TARGET="${LD}" Install the package: make install Details on this package are located in Section 10.10.2, “Contents of GCC.”

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6.5. Ncurses-5.6
The Ncurses package contains libraries for terminal-independent handling of character screens.

--with-shared This tells Ncurses to create a shared library. --without-debug This tells Ncurses not to build with debug information. --without-ada This ensures that Ncurses does not build support for the Ada compiler which may be present on the host but will not be available when building the final system. --enable-overwrite This tells Ncurses to install its header files into /tools/include, instead /tools/include/ncurses, to ensure that other packages can find the Ncurses headers successfully. --with-build-cc=gcc This tells Ncurses what type of compiler we are using. Compile the package: make Install the package: make install Details on this package are located in Section 10.17.2, “Contents of Ncurses.” of

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6.6. Bash-3.2
The Bash package contains the Bourne-Again SHell.

6.6.1. Installation of Bash
The following patch contains updates from the maintainer. The maintainer of Bash only releases these patches to fix serious issues: patch -Np1 -i ../bash-3.2-fixes-8.patch When bash is cross-compiled, it cannot test for the presence of named pipes, amoung other things. If you used su to become an unprivileged user, this combination will cause Bash to build without process substitution, which will break one of the c++ test scripts in glibc. The following prevents future problems by skipping tests that can not run while cross-compiling or that do not run properly: cat > config.cache << "EOF" ac_cv_func_mmap_fixed_mapped=yes ac_cv_func_strcoll_works=yes ac_cv_func_working_mktime=yes bash_cv_func_sigsetjmp=present bash_cv_getcwd_malloc=yes bash_cv_job_control_missing=present bash_cv_printf_a_format=yes bash_cv_sys_named_pipes=present bash_cv_ulimit_maxfds=yes bash_cv_under_sys_siglist=yes bash_cv_unusable_rtsigs=no gt_cv_int_divbyzero_sigfpe=yes EOF Prepare Bash for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} \ --without-bash-malloc --cache-file=config.cache
The meaning of the configure option:

--without-bash-malloc This option turns off the use of Bash's memory allocation (malloc) function which is known to cause segmentation faults. By turning this option off, Bash will use the malloc functions from Glibc which are more stable. Compile the package: make Install the package: make install 55

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Make a link for programs that use sh for a shell: ln -sv bash /tools/bin/sh Details on this package are located in Section 10.27.2, “Contents of Bash.”

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6.7. Bzip2-1.0.4
The Bzip2 package contains programs for compressing and decompressing files. Compressing text files with bzip2 yields a much better compression percentage than with the traditional gzip.

6.7.1. Installation of Bzip2
Bzip2's default Makefile target automatically runs the testsuite as well. Disable the tests since they won't work on a multi-architecture build: cp -v Makefile{,.orig} sed -e 's@^\(all:.*\) test@\1@g' Makefile.orig > Makefile The Bzip2 package does not contain a configure script. Compile it with: make CC="${CC}" AR="${AR}" RANLIB="${RANLIB}" Install the package: make PREFIX=/tools install Details on this package are located in Section 10.28.2, “Contents of Bzip2.”

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6.8. Coreutils-6.9
The Coreutils package contains utilities for showing and setting the basic system characteristics.

6.8.1. Installation of Coreutils
The following command renames the internal implementation of futimens to gl_futimens as newer versions of Glibc provide an incompatible version: sed -i "s/futimens/gl_&/" $(grep -lr futimens *) Configure can not properly determine how to get free space when cross-compiling, Without putting the following entry into config.cache the df program will not be built. echo "fu_cv_sys_stat_statfs2_bsize=yes" > config.cache Prepare Coreutils for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} \ --cache-file=config.cache When we changed the futimens references, one of the files we updated was touch.c. That change means the man Makefile will try to regenerate the man page for touch, by executing the compiled touch program. If the target architecture cannot be executed by the host system, the build will fail. The following command fixes this by giving the man page a newer timestamp than its corresponding source file: touch man/touch.1 Compile the package: make Install the package: make install Details on this package are located in Section 10.13.2, “Contents of Coreutils.”

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6.9. Diffutils-2.8.7
The Diffutils package contains programs that show the differences between files or directories.

6.9.1. Installation of Diffutils
Prepare Diffutils for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.29.2, “Contents of Diffutils.”

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6.10. Findutils-4.2.32
The Findutils package contains programs to find files. These programs are provided to recursively search through a directory tree and to create, maintain, and search a database (often faster than the recursive find, but unreliable if the database has not been recently updated).

6.10.1. Installation of Findutils
Prepare Findutils for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.31.2, “Contents of Findutils.”

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6.11. Zlib-1.2.3
The Zlib package contains compression and decompression routines used by some programs.

--shared Tells Zlib to build its shared library. Compile the package: make Install the package: make install Details on this package are located in Section 10.24.2, “Contents of Zlib.”

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6.12. File-4.23
The File package contains a utility for determining the type of a given file or files.

6.12.1. Installation of File
Prepare File for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.30.2, “Contents of File.”

6.13.1. Installation of Gawk
Prepare Gawk for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.32.2, “Contents of Gawk.”

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6.14. Gettext-0.17
The Gettext package contains utilities for internationalization and localization. These allow programs to be compiled with NLS (Native Language Support), enabling them to output messages in the user's native language.

6.14.1. Installation of Gettext
Only the programs in the gettext-tools directory need to be installed for the temp-system: cd gettext-tools When cross-compiling the Gettext configure script assumes we don't have a working wcwidth when we do. The following will fix possible compilation errors because of this assumption: echo "gl_cv_func_wcwidth_works=yes" > config.cache Prepare Gettext for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} \ --disable-shared --cache-file=config.cache
The meaning of the configure options:

--disable-shared This tells Gettext not to create a shared library. Compile the package: make -C gnulib-lib make -C src msgfmt Install the msgfmt binary: cp -v src/msgfmt /tools/bin Details on this package are located in Section 10.33.2, “Contents of Gettext.”

--disable-perl-regexp This ensures that the grep program does not get linked against a Perl Compatible Regular Expression (PCRE) library that may be present on the host but will not be available when building the final system. Compile the package: make Install the package: make install Details on this package are located in Section 10.34.2, “Contents of Grep.”

6.16.1. Installation of Gzip
The following command renames the internal implementation of futimens to gl_futimens as newer versions of Glibc provide an incompatible version: sed -i "s/futimens/gl_&/" $(grep -lr futimens *) Prepare Gzip for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.36.2, “Contents of Gzip.”

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6.17. Make-3.81
The Make package contains a program for compiling packages.

6.17.1. Installation of Make
Prepare Make for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.40.2, “Contents of Make.”

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6.18. Patch-2.5.9
The Patch package contains a program for modifying or creating files by applying a “patch” file typically created by the diff program.

6.18.1. Installation of Patch
Prepare Patch for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.44.2, “Contents of Patch.”

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6.19. Sed-4.1.5
The Sed package contains a stream editor.

6.19.1. Installation of Sed
Prepare Sed for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make install Details on this package are located in Section 10.11.2, “Contents of Sed.”

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6.20. Tar-1.20
The Tar package contains an archiving program.

6.20.1. Installation of Tar
TAR utilizes UTF-8 capability, without the following command the UTF-8 sections of the build will fail: echo "gl_cv_func_wcwidth_works=yes" >> config.cache Prepare Tar for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} \ --cache-file=config.cache Compile the package: make Install the package: make install Details on this package are located in Section 10.49.2, “Contents of Tar.”

6.21.1. Installation of Texinfo
The following patch fixes a build error due to mbstate being undefined: patch -Np1 -i ../texinfo-4.11-mbstate_fix-1.patch Prepare Texinfo for compilation: ./configure --prefix=/tools \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make -C tools/gnulib/lib make -C tools make Install the package: make install Details on this package are located in Section 10.50.2, “Contents of Texinfo.”

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6.22. To Boot or to Chroot?
There are two different ways you can proceed from this point to build the final system. You can build a kernel, a bootloader, and a few other utilities, boot into the temporary system, and build the rest there. Alternatively, you can chroot into the temporary system. The boot method is needed when you are building on a different architecture. For example, if you are building a PowerPC system from an x86, you can't chroot. The chroot method is for when you are building on the same architecture. If you are building on, and for, an x86 system, you can simply chroot. The rule of thumb here is if the architectures match and you are running the same series kernel you can just chroot. If you aren't running the same series kernel, or are wanting to run a different ABI, you will need to use the boot option. If you are in any doubt about this, you can try the following commands to see if you can chroot: /tools/lib/libc.so.6 /tools/bin/gcc -v If either of these commands fail, you will have to follow the boot method. To chroot, you will also need a Linux Kernel-2.6.x (having been compiled with GCC-3.0 or greater). The reason for the kernel version requirement is that, without it, thread-local storage support in Binutils will not be built and the Native POSIX Threading Library (NPTL) test suite will segfault. To check your kernel version, run cat /proc/version - if it does not say that you are running a 2.6.2 or later Linux kernel, compiled with GCC 3.0 or later, you cannot chroot. For the boot method, follow If You Are Going to Boot. For the chroot method, follow If You Are Going to Chroot.

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Chapter 7. If You Are Going to Boot
7.1. Introduction
This chapter shows how to complete the build of temporary tools to create a minimal system that will be used to boot the target machine and to build the final system packages. There are a few additional packages that will need to be installed to allow you to boot the minimal system. Some of these packages will be installed onto root or in /usr on the CLFS partition (${CLFS}/bin, ${CLFS}/usr/bin, etc...), rather than /tools, using the "DESTDIR" option with make. This will require the clfs user to have write access to the rest of the CLFS partition, so you will need to temporarily change the ownership of ${CLFS} to the clfs user. Run the following command as root: chown -v clfs ${CLFS}

7.2. Creating Directories
It is time to create some structure in the CLFS file system. Create a standard directory tree by issuing the following commands: mkdir -pv ${CLFS}/{bin,boot,dev,{etc/,}opt,home,lib,mnt} mkdir -pv ${CLFS}/{proc,media/{floppy,cdrom},sbin,srv,sys} mkdir -pv ${CLFS}/var/{lock,log,mail,run,spool} mkdir -pv ${CLFS}/var/{opt,cache,lib/{misc,locate},local} install -dv -m 0750 ${CLFS}/root install -dv -m 1777 ${CLFS}{/var,}/tmp mkdir -pv ${CLFS}/usr/{,local/}{bin,include,lib,sbin,src} mkdir -pv ${CLFS}/usr/{,local/}share/{doc,info,locale,man} mkdir -pv ${CLFS}/usr/{,local/}share/{misc,terminfo,zoneinfo} mkdir -pv ${CLFS}/usr/{,local/}share/man/man{1,2,3,4,5,6,7,8} for dir in ${CLFS}/usr{,/local}; do ln -sv share/{man,doc,info} $dir done Directories are, by default, created with permission mode 755, but this is not desirable for all directories. In the commands above, two changes are made—one to the home directory of user root, and another to the directories for temporary files. The first mode change ensures that not just anybody can enter the /root directory—the same as a normal user would do with his or her home directory. The second mode change makes sure that any user can write to the /tmp and /var/tmp directories, but cannot remove another user's files from them. The latter is prohibited by the so-called “sticky bit,” the highest bit (1) in the 1777 bit mask.

7.2.1. FHS Compliance Note
The directory tree is based on the Filesystem Hierarchy Standard (FHS) (available at http://www.pathname. com/fhs/). In addition to the tree created above, this standard stipulates the existence of /usr/local/games and /usr/share/games. The FHS is not precise as to the structure of the /usr/local/share subdirectory, so we create only the directories that are needed. However, feel free to create these directories if you prefer to conform more strictly to the FHS. 73

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7.3. Creating Essential Symlinks
Some programs use hard-wired paths to programs which do not exist yet. In order to satisfy these programs, create a number of symbolic links which will be replaced by real files throughout the course of the next chapter after the software has been installed. ln ln ln ln ln -sv -sv -sv -sv -sv /tools/bin/{bash,cat,echo,grep,pwd,rm,stty} ${CLFS}/bin /tools/bin/file ${CLFS}/usr/bin /tools/lib/libgcc_s.so{,.1} ${CLFS}/usr/lib /tools/lib/libstd*so* ${CLFS}/usr/lib bash ${CLFS}/bin/sh

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7.4. E2fsprogs-1.40.4
The E2fsprogs package contains the utilities for handling the ext2 file system. It also supports the ext3 journaling file system.

7.4.1. Installation of E2fsprogs
The E2fsprogs documentation recommends that the package be built in a subdirectory of the source tree: mkdir -v build cd build Prepare E2fsprogs for compilation: ../configure --prefix=/tools \ --enable-elf-shlibs --disable-evms --with-cc=${CC} --with-linker=${LD} \ --build=${CLFS_HOST} --host=${CLFS_TARGET}
The meaning of the configure options:

--enable-elf-shlibs This creates the shared libraries which some programs in this package use. --disable-evms This disables the building of the Enterprise Volume Management System (EVMS) plugin. This plugin is not up-to-date with the latest EVMS internal interfaces and EVMS is not installed as part of a base CLFS system, so the plugin is not required. See the EVMS website at http://evms.sourceforge.net/ for more information regarding EVMS. Compile the package: make Install the binaries, documentation and shared libraries: make DESTDIR="${CLFS}" install Install the static libraries and headers: make install-libs Create needed symlinks for a bootable system: ln -sv /tools/sbin/{fsck.ext2,fsck.ext3,e2fsck} ${CLFS}/sbin Details on this package are located in Section 10.12.2, “Contents of E2fsprogs.”

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7.5. Sysvinit-2.86
The Sysvinit package contains programs for controlling the startup, running, and shutdown of the system.

7.6. Module-Init-Tools-3.4
The Module-Init-Tools package contains programs for handling kernel modules in Linux kernels greater than or equal to version 2.5.47.

7.6.1. Installation of Module-Init-Tools
The tarball only contains sgml source for the manual pages. The following patch contains the result of processing this through docbook2man which we do not build as part of a basic clfs install : patch -Np1 -i ../module-init-tools-3.4-manpages-1.patch Prepare Module-Init-Tools for compilation: ./configure --prefix=/ \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make DESTDIR=${CLFS} install Details on this package are located in Section 10.43.2, “Contents of Module-Init-Tools.”

7.7.1. Installation of Util-linux-ng
Prepare Util-linux-ng for compilation: ./configure --build=${CLFS_HOST} \ --host=${CLFS_TARGET} --enable-login-utils \ --disable-makeinstall-chown Compile the package: make Install the package: make DESTDIR=${CLFS} install Details on this package are located in Section 10.52.3, “Contents of Util-linux-ng.”

7.8.1. Installation of Udev
Compile the package: make CROSS_COMPILE="${CLFS_TARGET}-" CC="${CC}" LD="${CC}" Install the package: make DESTDIR=${CLFS} install Details on this package are located in Section 10.51.2, “Contents of Udev.”

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7.9. Creating the passwd, group, and log Files
In order for user root to be able to login and for the name “root” to be recognized, there must be relevant entries in the /etc/passwd and /etc/group files. Create the ${CLFS}/etc/passwd file by running the following command: cat > ${CLFS}/etc/passwd << "EOF" root::0:0:root:/root:/bin/bash EOF The actual password for root (the “::” used here is just a placeholder and allow you to login with no password) will be set later.
Additional users you may want to add:

bin:x:1:1:bin:/bin:/bin/false Can be useful for compatibility with legacy applications. daemon:x:2:6:daemon:/sbin:/bin/false It is often recommended to use an unprivileged User ID/Group ID for daemons to run as, in order to limit their access to the system. adm:x:3:16:adm:/var/adm:/bin/false Was used for programs that performed administrative tasks. lp:x:10:9:lp:/var/spool/lp:/bin/false Used by programs for printing mail:x:30:30:mail:/var/mail:/bin/false Often used by email programs news:x:31:31:news:/var/spool/news:/bin/false Often used for network news servers uucp:x:32:32:uucp:/var/spool/uucp:/bin/false Often used for Unix-to-Unix Copy of files from one server to the next operator:x:50:0:operator:/root:/bin/bash Often used to allow system operators to access the system postmaster:x:51:30:postmaster:/var/spool/mail:/bin/false Generally used as an account that receives all the information of troubles with the mail server nobody:x:65534:65534:nobody:/:/bin/false Used by NFS

adm:x:16:root,adm,daemon All users in this group are allowed to do administrative tasks console:x:17: This group has direct access to the console cdrw:x:18: This group is allowed to use the CDRW drive mail:x:30:mail Used by MTAs (Mail Transport Agents) news:x:31:news Used by Network News Servers uucp:x:32:uucp Used by the Unix-to-Unix copy users users:x:1000: The default GID used by shadow for new users nogroup:x:65533: This is a default group used by some programs that do not require a group nobody:x:65534: This is used by NFS The created groups are not part of any standard—they are groups decided on in part by the requirements of the Udev configuration in the final system, and in part by common convention employed by a number of existing Linux distributions. The Linux Standard Base (LSB, available at http://www.linuxbase.org) recommends only that, besides 82

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 the group “root” with a Group ID (GID) of 0, a group “bin” with a GID of 1 be present. All other group names and GIDs can be chosen freely by the system administrator since well-written programs do not depend on GID numbers, but rather use the group's name. The login, agetty, and init programs (and others) use a number of log files to record information such as who was logged into the system and when. However, these programs will not write to the log files if they do not already exist. Initialize the log files and give them proper permissions: touch ${CLFS}/var/run/utmp ${CLFS}/var/log/{btmp,lastlog,wtmp} chmod -v 664 ${CLFS}/var/run/utmp ${CLFS}/var/log/lastlog chmod -v 600 ${CLFS}/var/log/btmp The /var/run/utmp file records the users that are currently logged in. The /var/log/wtmp file records all logins and logouts. The /var/log/lastlog file records when each user last logged in. The /var/log/btmp file records the bad login attempts.

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7.10. Linux-2.6.24.7
The Linux package contains the Linux kernel.

7.10.1. Installation of the kernel
Warning
Here a temporary cross-compiled kernel will be built. When configuring it, select the minimal amount of options required to boot the target machine and build the final system. I.e., no support for sound, printers, etc. will be needed. Also, try to avoid the use of modules if possible, and don't use the resulting kernel image for production systems. A number of vulnerabilities have come to light after the stable kernel team stopped supporting 2.6.24. The following patch addresses them: patch -Np1 -i ../linux-2.6.24.7-security_fixes-1.patch Building the kernel involves a few steps—configuration, compilation, and installation. Read the README file in the kernel source tree for alternative methods to the way this book configures the kernel. Prepare for compilation by running the following command: make mrproper This ensures that the kernel tree is absolutely clean. The kernel team recommends that this command be issued prior to each kernel compilation. Do not rely on the source tree being clean after un-tarring. Configure the kernel via a menu-driven interface: make ARCH=i386 CROSS_COMPILE=${CLFS_TARGET}- menuconfig Compile the kernel image and modules: make ARCH=i386 CROSS_COMPILE=${CLFS_TARGET}If the use of kernel modules can't be avoided, an /etc/modprobe.conf file may be needed. Information pertaining to modules and kernel configuration is located in the kernel documentation in the Documentation directory of the kernel sources tree. The modprobe.conf man page may also be of interest. Be very careful when reading other documentation relating to kernel modules because it usually applies to 2.4.x kernels only. As far as we know, kernel configuration issues specific to Hotplug and Udev are not documented. The problem is that Udev will create a device node only if Hotplug or a user-written script inserts the corresponding module into the kernel, and not all modules are detectable by Hotplug. Note that statements like the one below in the /etc/modprobe.conf file do not work with Udev: alias char-major-XXX some-module Install the modules, if the kernel configuration uses them: make ARCH=i386 CROSS_COMPILE=${CLFS_TARGET}- \ INSTALL_MOD_PATH=${CLFS} modules_install 84

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 After kernel compilation is complete, additional steps are required to complete the installation. Some files need to be copied to the ${CLFS}/boot directory. Issue the following command to install the kernel: cp -v arch/i386/boot/bzImage ${CLFS}/boot/clfskernel-2.6.24.7 System.map is a symbol file for the kernel. It maps the function entry points of every function in the kernel API, as well as the addresses of the kernel data structures for the running kernel. Issue the following command to install the map file: cp -v System.map ${CLFS}/boot/System.map-2.6.24.7 The kernel configuration file .config produced by the make menuconfig step above contains all the configuration selections for the kernel that was just compiled. It is a good idea to keep this file for future reference: cp -v .config ${CLFS}/boot/config-2.6.24.7 Details on this package are located in Section 12.3.2, “Contents of Linux.”

7.11.1. Installation of GRUB
GRUB has an issue where it sometimes doesn't detect the disk geometry correctly when used with Linux 2.6, resulting in the error message Error 24: Attempt to access block outside partition. The following patch contains a fix for this issue as well as various fixes for raid controllers and support for the new Intel Mac: patch -Np1 -i ../grub-0.97-fixes-1.patch This package is known to have issues when its default optimization flags (including the -march and -mcpu options) are changed. If any environment variables that override default optimizations have been defined, such as CFLAGS and CXXFLAGS, unset them when building GRUB. Prepare GRUB for compilation: ./configure --prefix=/usr \ --build=${CLFS_HOST} --host=${CLFS_TARGET} Compile the package: make Install the package: make DESTDIR=${CLFS} install mkdir -v ${CLFS}/boot/grub cp -v ${CLFS}/usr/lib/grub/*/stage{1,2} ${CLFS}/boot/grub The directory in ${CLFS}/usr/lib/grub (its name depends on your arch) contains a number of *stage1_ 5 files, different ones for different file systems. Review the files available and copy the appropriate ones to the ${CLFS}/boot/grub directory. Most users will copy the e2fs_stage1_5 and/or reiserfs_stage1_5 files. Details on this package are located in Section 10.54.2, “Contents of GRUB.”

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7.12. Setting Up the Environment
The new instance of the shell that will start when the system is booted is a login shell, which will read .bash_ profile file. Create the .bash_profile file now: cat > ${CLFS}/root/.bash_profile << "EOF" set +h PS1='\u:\w\$ ' LC_ALL=POSIX PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin:/tools/sbin export LC_ALL PATH PS1 EOF The LC_ALL variable controls the localization of certain programs, making their messages follow the conventions of a specified country. Setting LC_ALL to “POSIX” or “C” (the two are equivalent) ensures that everything will work as expected on your temporary system. By putting /tools/bin at the end of the standard PATH, all the programs installed in Constructing a Temporary System are only picked up by the shell if they have not yet been built on the target system. This configuration forces use of the final system binaries as they are built over the temp-system, minimising the chance of final system programs being built against the temp-system.

7.13. Creating the /etc/fstab File
The /etc/fstab file is used by some programs to determine where file systems are to be mounted by default, which must be checked, and in which order. Create a new file systems table like this: cat > ${CLFS}/etc/fstab << "EOF" # Begin /etc/fstab # file system # mount-point type options dump fsck order 1 0 0 0 0 0

Replace [xxx], [yyy], and [fff] with the values appropriate for the system, for example, hda2, hda5, and ext2. For details on the six fields in this file, see man 5 fstab. The /dev/shm mount point for tmpfs is included to allow enabling POSIX-shared memory. The kernel must have the required support built into it for this to work (more about this is in the next section). Please note that very little software currently uses POSIX-shared memory. Therefore, consider the /dev/shm mount point optional. For more information, see Documentation/filesystems/tmpfs.txt in the kernel source tree.

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7.14. CLFS-Bootscripts-1.1.0
The CLFS-Bootscripts package contains a set of scripts to start/stop the CLFS system at bootup/shutdown.

7.14.1. Installation of CLFS-Bootscripts
Install the package: make DESTDIR=${CLFS} install-minimal The setclock script reads the time from the hardware clock, also known as the BIOS or the Complementary Metal Oxide Semiconductor (CMOS) clock. If the hardware clock is set to UTC, this script will convert the hardware clock's time to the local time using the /etc/localtime file (which tells the hwclock program which timezone the user is in). There is no way to detect whether or not the hardware clock is set to UTC, so this needs to be configured manually. If you do not know whether or not the hardware clock is set to UTC, you can find out after you have booted the new machine by running the hwclock --localtime --show command, and if necessary editing the /etc/sysconfig/clock script. The worst that will happen if you make a wrong guess here is that the time displayed will be wrong. Change the value of the UTC variable below to a value of 0 (zero) if the hardware clock is not set to UTC time. cat > ${CLFS}/etc/sysconfig/clock << "EOF" # Begin /etc/sysconfig/clock UTC=1 # End /etc/sysconfig/clock EOF Details on this package are located in Section 11.2.2, “Contents of CLFS-Bootscripts.”

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7.15. Populating /dev
7.15.1. Creating Initial Device Nodes
Note
The commands in the remainder of the book should be run as the root user. Also, double-check that ${CLFS} is set as root. When the kernel boots the system, it requires the presence of a few device nodes, in particular the console and null devices. The device nodes will be created on the hard disk so that they are available before udev has been started, and additionally when Linux is started in single user mode (hence the restrictive permissions on console). Create these by running the following commands: mknod -m 600 ${CLFS}/dev/console c 5 1 mknod -m 666 ${CLFS}/dev/null c 1 3

7.16. Changing Ownership
Currently, the ${CLFS} directory and all of its subdirectories are owned by the user clfs, a user that exists only on the host system. For security reasons, the ${CLFS} root directory and all of it subdirectories should be owned by root. Change the ownership for ${CLFS} and its subdirectories by running this command: chown -Rv root:root ${CLFS}

7.17. Making the Temporary System Bootable
Boot loading can be a complex area, so a few cautionary words are in order. Be familiar with the current boot loader and any other operating systems present on the hard drive(s) that need to be bootable. Make sure that an emergency boot disk is ready to “rescue” the computer if the computer becomes unusable (un-bootable). Earlier, we compiled and installed the GRUB boot loader software in preparation for this step. The procedure involves writing some special GRUB files to specific locations on the hard drive. We highly recommend creating a GRUB boot floppy diskette as a backup. Insert a blank floppy diskette and run the following commands: dd if=${CLFS}/boot/grub/stage1 of=/dev/fd0 bs=512 count=1 dd if=${CLFS}/boot/grub/stage2 of=/dev/fd0 bs=512 seek=1 Remove the diskette and store it somewhere safe. Now, run the grub shell: grub GRUB uses its own naming structure for drives and partitions in the form of (hdn,m), where n is the hard drive number and m is the partition number, both starting from zero. For example, partition hda1 is (hd0,0) to GRUB and hdb3 is (hd1,2). In contrast to Linux, GRUB does not consider CD-ROM drives to be hard drives. For example, if using a CD on hdb and a second hard drive on hdc, that second hard drive would still be (hd1). Using the above information, determine the appropriate designator for the root partition (or boot partition, if a separate one is used). For the following example, it is assumed that the root (or separate boot) partition is hda4. 89

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Tell GRUB where to search for its stage{1,2} files. The Tab key can be used everywhere to make GRUB show the alternatives: root (hd0,3)

Warning
The following command will overwrite the current boot loader. Do not run the command if this is not desired, for example, if using a third party boot manager to manage the Master Boot Record (MBR). In this scenario, it would make more sense to install GRUB into the “boot sector” of the CLFS partition. In this case, this next command would become setup (hd0,3). Tell GRUB to install itself into the MBR of hda: setup (hd0) If all went well, GRUB will have reported finding its files in /boot/grub. That's all there is to it. Quit the grub shell: quit Create a “menu list” file defining GRUB's boot menu: cat > ${CLFS}/boot/grub/menu.lst << "EOF" # Begin /boot/grub/menu.lst # By default boot the first menu entry. default 0 # Allow 30 seconds before booting the default. timeout 30 # Use prettier colors. color green/black light-green/black # The first entry is for CLFS. title CLFS 1.1.0 root (hd0,3) kernel /boot/clfskernel-2.6.24.7 root=/dev/hda4 EOF Add an entry for the host distribution if desired. It might look like this: cat >> ${CLFS}/boot/grub/menu.lst << "EOF" title Red Hat root (hd0,2) kernel /boot/kernel-2.6.5 root=/dev/hda3 initrd /boot/initrd-2.6.5 EOF 90

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7.18. What to do next
Now you're at the point to get your ${CLFS} directory copied over to your target machine. The easiest method would be to tar it up and copy the file. tar -jcvf ${CLFS}.tar.bz2 ${CLFS}

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Chapter 8. If You Are Going to Chroot
8.1. Introduction
This chapter shows how to prepare a chroot jail to build the final system packages into.

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8.2. E2fsprogs-1.40.4
The E2fsprogs package contains the utilities for handling the ext2 file system. It also supports the ext3 journaling file system.

8.2.1. Installation of E2fsprogs
The E2fsprogs documentation recommends that the package be built in a subdirectory of the source tree: mkdir -v build cd build Prepare E2fsprogs for compilation: ../configure --prefix=/tools \ --enable-elf-shlibs --disable-evms --with-cc=${CC} --with-linker=${LD} \ --build=${CLFS_HOST} --host=${CLFS_TARGET}
The meaning of the configure options:

--enable-elf-shlibs This creates the shared libraries which some programs in this package use. --disable-evms This disables the building of the Enterprise Volume Management System (EVMS) plugin. This plugin is not up-to-date with the latest EVMS internal interfaces and EVMS is not installed as part of a base CLFS system, so the plugin is not required. See the EVMS website at http://evms.sourceforge.net/ for more information regarding EVMS. Compile the package: make libs Install the static libraries and headers: make install-libs
The meaning of the make option:

install-libs This command will only install the e2fsprogs libraries. Details on this package are located in Section 10.12.2, “Contents of E2fsprogs.”

8.4. Mounting Virtual Kernel File Systems
Note
The commands in the remainder of the book should be run as the root user. Also, double-check that ${CLFS} is set as root. Various file systems exported by the kernel are used to communicate to and from the kernel itself. These file systems are virtual in that no disk space is used for them. The content of the file systems resides in memory. Begin by creating directories onto which the file systems will be mounted: mkdir -pv ${CLFS}/{dev,proc,sys} Now mount the file systems: mount -vt proc proc ${CLFS}/proc mount -vt sysfs sysfs ${CLFS}/sys Remember that if for any reason you stop working on the CLFS system and start again later, it is important to check that these file systems are mounted again before entering the chroot environment. Two device nodes, /dev/console and /dev/null, are required to be present on the filesystem. These are needed by the kernel even before starting Udev early in the boot process, so we create them here: mknod -m 600 ${CLFS}/dev/console c 5 1 mknod -m 666 ${CLFS}/dev/null c 1 3 Once the system is complete and booting, the rest of our device nodes are created by the Udev package. Since this package is not available to us right now, we must take other steps to provide device nodes under on the CLFS filesystem. We will use the “bind” option in the mount command to make our host system's /dev structure appear in the new CLFS filesystem: mount -v -o bind /dev ${CLFS}/dev Additional file systems will soon be mounted from within the chroot environment. To keep the host up to date, perform a “fake mount” for each of these now: mount -f -vt tmpfs tmpfs ${CLFS}/dev/shm mount -f -vt devpts -o gid=4,mode=620 devpts ${CLFS}/dev/pts

8.5. Before Entering the Chroot Environment
8.5.1. Determining if steps need to be taken
Before we can enter the chroot we have to make sure that the system is in the proper state. From this point on the ${CLFS_TARGET} enviornment variable will no longer exist, so it will have no bearing on the rest of the book. From this point on, most packages will rely on config.guess provided by Section 10.26, “Automake-1.10.1”. Packages that do not use autotools either do not care about the target triplet, or they have their own means of determining it's value. In both cases, The information about the host cpu used to determine the target triplet is gathered from the same place, uname -m. Executing this command outside of the chroot aswell as inside the chroot will have the exact same output. 95

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 If you're unsure if you're host and target have the same target triplet, you can use this test to determine what the hosts target triplet is and if you need to take any steps to ensure that you don't build for the wrong architecture. Extract the Section 10.26, “Automake-1.10.1” tarball and cd into the created directory. Then execute the following to see what they detected target triplet is by config.guess. lib/config.guess If the output of that command does not equal what is in ${CLFS_TARGET} then you need to read on. If it does then you can safely continue onto Section 8.6, “Entering the Chroot Environment”.

8.5.2. Using Setarch
If your host has a tool called setarch this may solve your problems. The reason for saying may is because on a architecture such as x86_64, using setarch linux32 uname -m will only ever output i686. It is not possible to get an output of i486 or i586. To test if setarch does everything you need it to, execute the following command from inside of the Section 10.26, “Automake-1.10.1” directory: setarch linux32 lib/config.guess If the output of the command above equals what is in ${CLFS_TARGET} then you have a viable solution. You can wrap the chroot command on the next page with setarch linux32. It will look like the following: setarch linux32 chroot "${CLFS}" /tools/bin/env -i \ HOME=/root TERM="${TERM}" PS1='\u:\w\$ ' \ PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \ /tools/bin/bash --login +h If setarch works for you then you can safely continue onto Section 8.6, “Entering the Chroot Environment”. If not, there is one more option covered in this book.

8.5.3. Using a Uname Hack
The Uname Hack is a kernel module that modifies the output of uname -m by directly changing the value of the detected machine type. The kernel module will save the original value and restore it when the module is unloaded. • Uname Hack (20080713) - 2 KB: Download: http://cross-lfs.org/files/extras/uname_hack-20080713.tar.bz2 MD5 sum: dd7694f28ccc6e6bfb326b1790adb5e9 Extract the tarball and cd into the created directory. To build the Uname Hack you must have the kernel sources for you currently running kernel available. Build the Uname Hack with the following or similar command: make uname_hack_fake_machine=i486
The meaning of the make and install options:

uname_hack_fake_machine=i486 This parameter sets the value that the uts machine type will be changed to. Alternativley this could be set to i586 or i686. 96

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 In the top level directory of the Uname Hack pacakage you should see a file named uname_hack.ko. As soon as that module is loaded into the running kernel the output of uname -m will be affected immediately system-wide. Load the kernel module with the following command: insmod uname_hack.ko To test if the Uname Hack is working properly, execute the following command from inside of the Section 10.26, “Automake-1.10.1” directory: lib/config.guess The output of the above command should be the same as the ${CLFS_TARGET} enviornment variable. If this is not the case, You can try and get help on the CLFS Support Mailing List or the IRC Channel. See Section 1.6, “Help” for more information.

8.6. Entering the Chroot Environment
It is time to enter the chroot environment to begin building and installing the final CLFS system. As user root, run the following command to enter the realm that is, at the moment, populated with only the temporary tools: chroot "${CLFS}" /tools/bin/env -i \ HOME=/root TERM="${TERM}" PS1='\u:\w\$ ' \ PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \ /tools/bin/bash --login +h The -i option given to the env command will clear all variables of the chroot environment. After that, only the HOME, TERM, PS1, and PATH variables are set again. The TERM=${TERM} construct will set the TERM variable inside chroot to the same value as outside chroot. This variable is needed for programs like vim and less to operate properly. If other variables are needed, such as CFLAGS or CXXFLAGS, this is a good place to set them again. From this point on, there is no need to use the CLFS variable anymore, because all work will be restricted to the CLFS file system. This is because the Bash shell is told that ${CLFS} is now the root (/) directory. Notice that /tools/bin comes last in the PATH. This means that a temporary tool will no longer be used once its final version is installed. This occurs when the shell does not “remember” the locations of executed binaries—for this reason, hashing is switched off by passing the +h option to bash. It is important that all the commands throughout the remainder of this chapter and the following chapters are run from within the chroot environment. If you leave this environment for any reason (rebooting for example), remember to first mount the proc and devpts file systems (discussed in the previous section) and enter chroot again before continuing with the installations. Note that the bash prompt will say I have no name! This is normal because the /etc/passwd file has not been created yet.

8.7. Changing Ownership
Currently, the /tools and /cross-tools directories are owned by the user clfs, a user that exists only on the host system. Although the /tools and /cross-tools directories can be deleted once the CLFS system has been finished, they can be retained to build additional CLFS systems. If the /tools and /cross-tools directories 97

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 are kept as is, the files are owned by a user ID without a corresponding account. This is dangerous because a user account created later could get this same user ID and would own the /tools directory and all the files therein, thus exposing these files to possible malicious manipulation. To avoid this issue, add the clfs user to the new CLFS system later when creating the /etc/passwd file, taking care to assign it the same user and group IDs as on the host system. Alternatively, assign the contents of the /tools and /cross-tools directories to user root by running the following commands: chown -Rv 0:0 /tools chown -Rv 0:0 /cross-tools The commands use 0:0 instead of root:root, because chown is unable to resolve the name “root” until the passwd file has been created.

8.8. Creating Directories
It is time to create some structure in the CLFS file system. Create a standard directory tree by issuing the following commands: mkdir -pv /{bin,boot,dev,{etc/,}opt,home,lib,mnt} mkdir -pv /{proc,media/{floppy,cdrom},sbin,srv,sys} mkdir -pv /var/{lock,log,mail,run,spool} mkdir -pv /var/{opt,cache,lib/{misc,locate},local} install -dv -m 0750 /root install -dv -m 1777 {/var,}/tmp mkdir -pv /usr/{,local/}{bin,include,lib,sbin,src} mkdir -pv /usr/{,local/}share/{doc,info,locale,man} mkdir -pv /usr/{,local/}share/{misc,terminfo,zoneinfo} mkdir -pv /usr/{,local/}share/man/man{1..8} for dir in /usr{,/local}; do ln -sv share/{man,doc,info} $dir done Directories are, by default, created with permission mode 755, but this is not desirable for all directories. In the commands above, two changes are made—one to the home directory of user root, and another to the directories for temporary files. The first mode change ensures that not just anybody can enter the /root directory—the same as a normal user would do with his or her home directory. The second mode change makes sure that any user can write to the /tmp and /var/tmp directories, but cannot remove another user's files from them. The latter is prohibited by the so-called “sticky bit,” the highest bit (1) in the 1777 bit mask.

8.8.1. FHS Compliance Note
The directory tree is based on the Filesystem Hierarchy Standard (FHS) (available at http://www.pathname. com/fhs/). In addition to the tree created above, this standard stipulates the existence of /usr/local/games and /usr/share/games. The FHS is not precise as to the structure of the /usr/local/share subdirectory, so we create only the directories that are needed. However, feel free to create these directories if you prefer to conform more strictly to the FHS. 98

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8.9. Creating Essential Symlinks
Some programs use hard-wired paths to programs which do not exist yet. In order to satisfy these programs, create a number of symbolic links which will be replaced by real files throughout the course of the next chapter after the software has been installed. ln ln ln ln ln -sv -sv -sv -sv -sv /tools/bin/{bash,cat,echo,grep,pwd,rm,stty} /bin /tools/bin/file /usr/bin /tools/lib/libgcc_s.so{,.1} /usr/lib /tools/lib/libstd* /usr/lib bash /bin/sh

8.10. Creating the passwd, group, and log Files
In order for user root to be able to login and for the name “root” to be recognized, there must be relevant entries in the /etc/passwd and /etc/group files. Create the /etc/passwd file by running the following command: cat > /etc/passwd << "EOF" root:x:0:0:root:/root:/bin/bash EOF The actual password for root (the “x” used here is just a placeholder) will be set later.
Additional users you may want to add:

bin:x:1:1:bin:/bin:/bin/false Can be useful for compatibility with legacy applications. daemon:x:2:6:daemon:/sbin:/bin/false It is often recommended to use an unprivileged User ID/Group ID for daemons to run as, in order to limit their access to the system. adm:x:3:16:adm:/var/adm:/bin/false Was used for programs that performed administrative tasks. lp:x:10:9:lp:/var/spool/lp:/bin/false Used by programs for printing mail:x:30:30:mail:/var/mail:/bin/false Often used by email programs news:x:31:31:news:/var/spool/news:/bin/false Often used for network news servers uucp:x:32:32:uucp:/var/spool/uucp:/bin/false Often used for Unix-to-Unix Copy of files from one server to the next operator:x:50:0:operator:/root:/bin/bash Often used to allow system operators to access the system postmaster:x:51:30:postmaster:/var/spool/mail:/bin/false Generally used as an account that receives all the information of troubles with the mail server nobody:x:65534:65534:nobody:/:/bin/false Used by NFS 99

adm:x:16:root,adm,daemon All users in this group are allowed to do administrative tasks console:x:17: This group has direct access to the console cdrw:x:18: This group is allowed to use the CDRW drive mail:x:30:mail Used by MTAs (Mail Transport Agents) news:x:31:news Used by Network News Servers uucp:x:32:uucp Used by the Unix-to-Unix copy users users:x:1000: The default GID used by shadow for new users nogroup:x:65533: This is a default group used by some programs that do not require a group nobody:x:65534: This is used by NFS The created groups are not part of any standard—they are groups decided on in part by the requirements of the Udev configuration in the final system, and in part by common convention employed by a number of existing Linux distributions. The Linux Standard Base (LSB, available at http://www.linuxbase.org) recommends only that, besides 100

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 the group “root” with a Group ID (GID) of 0, a group “bin” with a GID of 1 be present. All other group names and GIDs can be chosen freely by the system administrator since well-written programs do not depend on GID numbers, but rather use the group's name. To remove the “I have no name!” prompt, start a new shell. Since a full Glibc was installed in Constructing Cross-Compile Tools and the /etc/passwd and /etc/group files have been created, user name and group name resolution will now work. exec /tools/bin/bash --login +h Note the use of the +h directive. This tells bash not to use its internal path hashing. Without this directive, bash would remember the paths to binaries it has executed. To ensure the use of the newly compiled binaries as soon as they are installed, the +h directive will be used for the duration of the nexts chapters. The login, agetty, and init programs (and others) use a number of log files to record information such as who was logged into the system and when. However, these programs will not write to the log files if they do not already exist. Initialize the log files and give them proper permissions: touch chgrp chmod chmod /var/run/utmp /var/log/{btmp,lastlog,wtmp} -v utmp /var/run/utmp /var/log/lastlog -v 664 /var/run/utmp /var/log/lastlog -v 600 /var/log/btmp

The /var/run/utmp file records the users that are currently logged in. The /var/log/wtmp file records all logins and logouts. The /var/log/lastlog file records when each user last logged in. The /var/log/btmp file records the bad login attempts.

8.11. Mounting Kernel Filesystems
8.11.1. Mounting Additional Kernel Filesystems
Mount the proper virtual (kernel) file systems on the newly-created directories: mount -vt devpts -o gid=4,mode=620 none /dev/pts mount -vt tmpfs none /dev/shm The mount commands executed above may result in the following warning message: can't open /etc/fstab: No such file or directory. This file—/etc/fstab—has not been created yet but is also not required for the file systems to be properly mounted. As such, the warning can be safely ignored.

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Part V. Building the CLFS System

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Chapter 9. Constructing Testsuite Tools
9.1. Introduction
This chapter builds the tools needed to run the tests that the packages have. I.e., make check. Tcl, Expect, and DejaGNU are needed for the GCC and Binutils testsuites, and Tree is used by the Udev testsuite. Installing four packages for testing purposes may seem excessive, but it is very reassuring, if not essential, to know that the most important tools are working properly.

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9.2. Tcl-8.4.16
The Tcl package contains the Tool Command Language.

9.2.1. Installation of Tcl
Prepare Tcl for compilation: cd unix ./configure --prefix=/tools Build the package: make Install the package: make install Tcl's private header files are needed for the next package, Expect. Install them into /tools: make install-private-headers Now make a necessary symbolic link: ln -sv tclsh8.4 /tools/bin/tclsh

Short Descriptions
tclsh8.4 tclsh libtcl8.4.so The Tcl command shell A link to tclsh8.4 The Tcl library

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9.3. Expect-5.43.0
The Expect package contains a program for carrying out scripted dialogues with other interactive programs.

9.3.1. Installation of Expect
The following sed tells configure to look for libraries in ${libdir}, not just in /tools/lib: sed -i '/EXP_LIB_SPEC=/s@${exec_prefix}/lib@${libdir}@' configure Fix a bug that can result in false failures during the GCC test suite run: patch -Np1 -i ../expect-5.43.0-spawn-2.patch Now prepare Expect for compilation: ./configure --prefix=/tools --with-tcl=/tools/lib \ --with-tclinclude=/tools/include
The meaning of the configure options:

--with-tcl=/tools/lib This ensures that the configure script finds the Tcl installation in the temporary testsuite-tools location. --with-tclinclude=/tools/include This explicitly tells Expect where to find Tcl's internal headers. Using this option avoids conditions where configure fails because it cannot automatically discover the location of the Tcl source directory. Build the package: make Install the package: make SCRIPTS="" install
The meaning of the make parameter:

SCRIPTS="" This prevents installation of the supplementary expect scripts, which are not needed.

Short Descriptions
expect Communicates with other interactive programs according to a script libexpect-5.43.a Contains functions that allow Expect to be used as a Tcl extension or to be used directly from C or C++ (without Tcl)

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9.4. DejaGNU-1.4.4
The DejaGNU package contains a framework for testing other programs.

Short Descriptions
runtest A wrapper script that locates the proper expect shell and then runs DejaGNU

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9.5. Tree-1.5.1.1
The Tree package contains a program that lists the directory structure in a graphical "tree" format. It is used by Udev for failures in its testsuite.

9.5.1. Installation of Tree
Compile the package: make Install the package: make prefix=/tools install
The meaning of the make parameters:

prefix=/tools This overrides the default prefix of /usr in the Makefile.

9.5.2. Contents of Tree
Installed program: tree

Short Descriptions
tree Tree will list contents of directories in a tree-like format.

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Chapter 10. Installing Basic System Software
10.1. Introduction
In this chapter, we enter the building site and start constructing the CLFS system in earnest. The installation of this software is straightforward. Although in many cases the installation instructions could be made shorter and more generic, we have opted to provide the full instructions for every package to minimize the possibilities for mistakes. The key to learning what makes a Linux system work is to know what each package is used for and why the user (or the system) needs it. For every installed package, a summary of its contents is given, followed by concise descriptions of each program and library the package installed. If using compiler optimizations, please review the optimization hint at http://hints.cross-lfs.org/optimization.txt. Compiler optimizations can make a program run slightly faster, but they may also cause compilation difficulties and problems when running the program. If a package refuses to compile when using optimization, try to compile it without optimization and see if that fixes the problem. Even if the package does compile when using optimization, there is the risk it may have been compiled incorrectly because of the complex interactions between the code and build tools. Also note that the -march and -mtune options may cause problems with the toolchain packages (Binutils, GCC and Glibc). The small potential gains achieved in using compiler optimizations are often outweighed by the risks. First-time builders of CLFS are encouraged to build without custom optimizations. The subsequent system will still run very fast and be stable at the same time. The order that packages are installed in this chapter needs to be strictly followed to ensure that no program accidentally acquires a path referring to /tools hard-wired into it. For the same reason, do not compile packages in parallel. Compiling in parallel may save time (especially on dual-CPU machines), but it could result in a program containing a hard-wired path to /tools, which will cause the program to stop working when that directory is removed. To keep track of which package installs particular files, a package manager can be used. For a general overview of different styles of package managers, please take a look at the next page.

10.2. Package Management
Package Management is an often-requested addition to the CLFS Book. A Package Manager allows tracking the installation of files making it easy to remove and upgrade packages. Before you begin to wonder, NO—this section will not talk about nor recommend any particular package manager. What it provides is a roundup of the more popular techniques and how they work. The perfect package manager for you may be among these techniques or may be a combination of two or more of these techniques. This section briefly mentions issues that may arise when upgrading packages. Some reasons why no specific package manager is recommended in CLFS or BLFS include: • Dealing with package management takes the focus away from the goals of these books—teaching how a Linux system is built. • There are multiple solutions for package management, each having its strengths and drawbacks. Including one that satisfies all audiences is difficult. There are some hints written on the topic of package management. Visit the Hints subproject and see if one of them fits your need. 108

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10.2.1. Upgrade Issues
A Package Manager makes it easy to upgrade to newer versions when they are released. Generally the instructions in the CLFS and BLFS Book can be used to upgrade to the newer versions. Here are some points that you should be aware of when upgrading packages, especially on a running system. • If one of the toolchain packages (Glibc, GCC or Binutils) needs to be upgraded to a newer minor version, it is safer to rebuild CLFS. Though you may be able to get by rebuilding all the packages in their dependency order, we do not recommend it. For example, if glibc-2.2.x needs to be updated to glibc-2.3.x, it is safer to rebuild. For micro version updates, a simple reinstallation usually works, but is not guaranteed. For example, upgrading from glibc-2.3.4 to glibc-2.3.5 will not usually cause any problems. • If a package containing a shared library is updated, and if the name of the library changes, then all the packages dynamically linked to the library need to be recompiled to link against the newer library. (Note that there is no correlation between the package version and the name of the library.) For example, consider a package foo-1.2.3 that installs a shared library with name libfoo.so.1. Say you upgrade the package to a newer version foo-1.2.4 that installs a shared library with name libfoo.so.2. In this case, all packages that are dynamically linked to libfoo.so.1 need to be recompiled to link against libfoo.so.2. Note that you should not remove the previous libraries until the dependent packages are recompiled. • If you are upgrading a running system, be on the lookout for packages that use cp instead of install to install files. The latter command is usually safer if the executable or library is already loaded in memory.

10.2.2. Package Management Techniques
The following are some common package management techniques. Before making a decision on a package manager, do some research on the various techniques, particularly the drawbacks of the particular scheme.

10.2.2.1. It is All in My Head!
Yes, this is a package management technique. Some folks do not find the need for a package manager because they know the packages intimately and know what files are installed by each package. Some users also do not need any package management because they plan on rebuilding the entire system when a package is changed.

10.2.2.2. Install in Separate Directories
This is a simplistic package management that does not need any extra package to manage the installations. Each package is installed in a separate directory. For example, package foo-1.1 is installed in /usr/pkg/foo-1.1 and a symlink is made from /usr/pkg/foo to /usr/pkg/foo-1.1. When installing a new version foo-1.2, it is installed in /usr/pkg/foo-1.2 and the previous symlink is replaced by a symlink to the new version. Environment variables such as PATH, LD_LIBRARY_PATH, MANPATH, INFOPATH and CPPFLAGS need to be expanded to include /usr/pkg/foo. For more than a few packages, this scheme becomes unmanageable.

10.2.2.3. Symlink Style Package Management
This is a variation of the previous package management technique. Each package is installed similar to the previous scheme. But instead of making the symlink, each file is symlinked into the /usr hierarchy. This removes the need to expand the environment variables. Though the symlinks can be created by the user to automate the creation, many package managers have been written using this approach. A few of the popular ones include Stow, Epkg, Graft, and Depot. 109

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 The installation needs to be faked, so that the package thinks that it is installed in /usr though in reality it is installed in the /usr/pkg hierarchy. Installing in this manner is not usually a trivial task. For example, consider that you are installing a package libfoo-1.1. The following instructions may not install the package properly: ./configure --prefix=/usr/pkg/libfoo/1.1 make make install The installation will work, but the dependent packages may not link to libfoo as you would expect. If you compile a package that links against libfoo, you may notice that it is linked to /usr/pkg/libfoo/1.1/lib/libfoo. so.1 instead of /usr/lib/libfoo.so.1 as you would expect. The correct approach is to use the DESTDIR strategy to fake installation of the package. This approach works as follows: ./configure --prefix=/usr make make DESTDIR=/usr/pkg/libfoo/1.1 install Most packages support this approach, but there are some which do not. For the non-compliant packages, you may either need to manually install the package, or you may find that it is easier to install some problematic packages into /opt.

10.2.2.4. Timestamp Based
In this technique, a file is timestamped before the installation of the package. After the installation, a simple use of the find command with the appropriate options can generate a log of all the files installed after the timestamp file was created. A package manager written with this approach is install-log. Though this scheme has the advantage of being simple, it has two drawbacks. If, during installation, the files are installed with any timestamp other than the current time, those files will not be tracked by the package manager. Also, this scheme can only be used when one package is installed at a time. The logs are not reliable if two packages are being installed on two different consoles.

10.2.2.5. LD_PRELOAD Based
In this approach, a library is preloaded before installation. During installation, this library tracks the packages that are being installed by attaching itself to various executables such as cp, install, mv and tracking the system calls that modify the filesystem. For this approach to work, all the executables need to be dynamically linked without the suid or sgid bit. Preloading the library may cause some unwanted side-effects during installation. Therefore, it is advised that one performs some tests to ensure that the package manager does not break anything and logs all the appropriate files.

10.2.2.6. Creating Package Archives
In this scheme, the package installation is faked into a separate tree as described in the Symlink style package management. After the installation, a package archive is created using the installed files. This archive is then used to install the package either on the local machine or can even be used to install the package on other machines. This approach is used by most of the package managers found in the commercial distributions. Examples of package managers that follow this approach are RPM (which, incidentally, is required by the Linux Standard Base Specification), pkg-utils, Debian's apt, and Gentoo's Portage system. A hint describing how to adopt this style of package management for CLFS systems is located at http://hints.cross-lfs.org//fakeroot.txt. 110

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10.3. About Test Suites, Again
In the final-system build, you are no longer cross-compiling so it is possible to run package testsuites. Some test suites are more important than others. For example, the test suites for the core toolchain packages—GCC, Binutils, and Glibc—are of the utmost importance due to their central role in a properly functioning system. The test suites for GCC and Glibc can take a very long time to complete, especially on slower hardware, but are strongly recommended. A common issue with running the test suites for Binutils and GCC is running out of pseudo terminals (PTYs). This can result in a high number of failing tests. This may happen for several reasons, but the most likely cause (if you chrooted) is that the host system does not have the devpts file system set up correctly. This issue is discussed in greater detail at http://trac.cross-lfs.org/wiki/faq#no-ptys. Sometimes package test suites will fail, but for reasons which the developers are aware of and have deemed non-critical. Consult the logs located at http://cross-lfs.org/testsuite-logs/clfs-1.1.0/ to verify whether or not these failures are expected. This site is valid for all tests throughout this book.

10.4.1. Installation of Perl
The following patch causes makedepend.sh to also remove <command-line> as well as <command line>: patch -Np1 -i ../perl-5.8.8-gcc42_fix-1.patch The following patch prevents perl from including asm/page.h which will no longer be available in headers provided by kernel 2.6.25 and forward: patch -Np1 -i ../perl-5.8.8-no_page_h-1.patch First adapt some hard-wired paths to the C library by applying the following patch: patch -Np1 -i ../perl-5.8.8-libc-2.patch Prepare Perl for compilation (make sure to get the 'Data/Dumper Fcntl IO POSIX' part of the command correct—they are all letters): ./configure.gnu --prefix=/tools \ -Dstatic_ext='Data/Dumper IO Fcntl POSIX' -Dcc="gcc"
The meaning of the configure option:

-Dstatic_ext='Data/Dumper IO Fcntl POSIX' This tells Perl to build the minimum set of static extensions needed for installing and testing the Glibc and Coreutils packages later in this chapter. Now we are ready to make our perl utilities: make perl utilities Although Perl comes with a test suite, it is not recommended to run it at this point. Only part of Perl was built and running make test now will cause the rest of Perl to be built as well, which is unnecessary at this point. The test suite can be run later in this chapter if desired. Install these tools and their libraries: cp -v perl pod/pod2man /tools/bin install -dv /tools/lib/perl5/5.8.8 cp -Rv lib/* /tools/lib/perl5/5.8.8 Finally, create a necessary symlink: ln -sv /tools/bin/perl /usr/bin Details on this package are located in Section 10.22.2, “Contents of Perl.”

10.5.1. Installation of Linux-Headers
For this step you will need the kernel tarballs. Install the header files that are common to all architectures: make mrproper make headers_check make INSTALL_HDR_PATH=dest headers_install cp -rv dest/include/* /usr/include

10.7.1. Installation of Glibc
Note
Some packages outside of CLFS suggest installing GNU libiconv in order to translate data from one encoding to another. The project's home page (http://www.gnu.org/software/libiconv/) says “This library provides an iconv() implementation, for use on systems which don't have one, or whose implementation cannot convert from/to Unicode.” Glibc provides an iconv() implementation and can convert from/to Unicode, therefore libiconv is not required on a CLFS system. The Glibc build system is self-contained and will install perfectly, even though the compiler specs file and linker are still pointing at /tools. The specs and linker cannot be adjusted before the Glibc install because the Glibc Autoconf tests would give false results and defeat the goal of achieving a clean build. The following patches merges all updates from the 2.7 Branch from the Glibc developers: patch -Np1 -i ../glibc-2.7-branch_update-1A.patch The following patch ensures that memcpy_chk, mempcpy_chk, and memset_chk are defined for i586. patch -Np1 -i ../glibc-2.7-i586_chk-2.patch The following patch fixes an issue that can cause localdef to segfault: patch -Np1 -i ../glibc-2.7-localedef_segfault-1.patch The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory: mkdir -v ../glibc-build cd ../glibc-build Prepare Glibc for compilation: CFLAGS="-march=$(cut -d- -f1 <<< $MACHTYPE) \ -mtune=generic -g -O2" ../glibc-2.7/configure --prefix=/usr \ --disable-profile --enable-add-ons --enable-kernel=2.6.0 \ --libexecdir=/usr/lib/glibc
The meaning of the new configure option:

--libexecdir=/usr/lib/glibc This changes the location of the pt_chown program from its default of /usr/libexec to /usr/lib/glibc. Compile the package: make 115

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Important
The test suite for Glibc is considered critical. Do not skip it under any circumstance. Test the results: make -k check >glibc-check-log 2>&1 ; grep Error glibc-check-log The Glibc test suite is highly dependent on certain functions of the host system, in particular the kernel. The posix/annexc test normally fails and you should see Error 1 (ignored) in the output. Apart from this, the Glibc test suite is always expected to pass. However, in certain circumstances, some failures are unavoidable. If a test fails because of a missing program (or missing symbolic link), or a segfault, you will see an error code greater than 127 and the details will be in the log. More commonly, tests will fail with Error 2 - for these, the contents of the corresponding .out file, e.g. posix/annexc.out may be informative. Here is a list of the most common issues: • The math tests, at least on i686, fail in the test-double and test-idouble tests with gcc-4.2.4 . These two failures in the math tests appear to be harmless. The math tests may also fail on systems where the CPU is not a relatively new genuine Intel or authentic AMD. Certain optimization settings are also known to be a factor here. • If you have mounted the CLFS partition with the noatime option, the atime test will fail. As mentioned in Section 2.4, “Mounting the New Partition”, do not use the noatime option while building CLFS. • When running on older and slower hardware, some tests can fail because of test timeouts being exceeded. Though it is a harmless message, the install stage of Glibc will complain about the absence of /etc/ld.so.conf. Prevent this warning with: touch /etc/ld.so.conf Install the package: make install

10.7.2. Internationalization
The locales that can make the system respond in a different language were not installed by the above command. Install them with: make localedata/install-locales To save time, an alternative to running the previous command (which generates and installs every locale listed in the glibc-2.7/localedata/SUPPORTED file) is to install only those locales that are wanted and needed. This can be achieved by using the localedef command. Information on this command is located in the INSTALL file in the Glibc

Some locales installed by the make localedata/install-locales command above are not properly supported by some applications that are in the CLFS and BLFS books. Because of the various problems that arise due to application programmers making assumptions that break in such locales, CLFS should not be used in locales that utilize multibyte character sets (including UTF-8) or right-to-left writing order. Numerous unofficial and unstable patches are required to fix these problems, and it has been decided by the CLFS developers not to support such complex locales at this time. This applies to the ja_JP and fa_IR locales as well—they have been installed only for GCC and Gettext tests to pass, and the watch program (part of the Procps package) does not work properly in them. Various attempts to circumvent these restrictions are documented in internationalization-related hints.

10.7.3. Configuring Glibc
The /etc/nsswitch.conf file needs to be created because, although Glibc provides defaults when this file is missing or corrupt, the Glibc defaults do not work well in a networked environment. The time zone also needs to be configured.

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Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Create a new file /etc/nsswitch.conf by running the following: cat > /etc/nsswitch.conf << "EOF" # Begin /etc/nsswitch.conf passwd: files group: files shadow: files hosts: files dns networks: files protocols: files services: files ethers: files rpc: files # End /etc/nsswitch.conf EOF To determine the local time zone, run the following script: tzselect After answering a few questions about the location, the script will output the name of the time zone (e.g., EST5EDT or Canada/Eastern). Then create the /etc/localtime file by running: cp -v --remove-destination /usr/share/zoneinfo/[xxx] \ /etc/localtime Replace [xxx] with the name of the time zone that tzselect provided (e.g., Canada/Eastern).
The meaning of the cp option:

--remove-destination This is needed to force removal of the already existing symbolic link. The reason for copying the file instead of using a symlink is to cover the situation where /usr is on a separate partition. This could be important when booted into single user mode.

10.7.4. Configuring The Dynamic Loader
By default, the dynamic loader (/lib/ld-linux.so.2) searches through /lib and /usr/lib for dynamic libraries that are needed by programs as they are run. However, if there are libraries in directories other than /lib and /usr/lib, these need to be added to the /etc/ld.so.conf file in order for the dynamic loader to find them. Two directories that are commonly known to contain additional libraries are /usr/local/lib and /opt/lib, so add those directories to the dynamic loader's search path.

Short Descriptions
catchsegv gencat getconf getent iconv iconvconfig ldconfig ldd lddlibc4 locale localedef mtrace nscd pcprofiledump pt_chown rpcgen rpcinfo sln Can be used to create a stack trace when a program terminates with a segmentation fault Generates message catalogues Displays the system configuration values for file system specific variables Gets entries from an administrative database Performs character set conversion Creates fastloading iconv module configuration files Configures the dynamic linker runtime bindings Reports which shared libraries are required by each given program or shared library Assists ldd with object files Tells the compiler to enable or disable the use of POSIX locales for built-in operations Compiles locale specifications Reads and interprets a memory trace file and displays a summary in human-readable format A daemon that provides a cache for the most common name service requests Dumps information generated by PC profiling A helper program for grantpt to set the owner, group and access permissions of a slave pseudo terminal Generates C code to implement the Remote Procecure Call (RPC) protocol Makes an RPC call to an RPC server A statically linked program that creates symbolic links 119

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 sprof tzselect xtrace zdump zic ld.so libSegFault libanl libbsd-compat libc libcrypt libdl libg libieee libm libmcheck libmemusage libnsl libnss libpcprofile libpthread libresolv librpcsvc librt libthread_db libutil Reads and displays shared object profiling data Asks the user about the location of the system and reports the corresponding time zone description Traces the execution of a program by printing the currently executed function The time zone dumper The time zone compiler The helper program for shared library executables The segmentation fault signal handler An asynchronous name lookup library Provides the portability needed in order to run certain Berkey Software Distribution (BSD) programs under Linux The main C library The cryptography library The dynamic linking interface library A runtime library for g++ The Institute of Electrical and Electronic Engineers (IEEE) floating point library The mathematical library Contains code run at boot Used by memusage (included in Glibc, but not built in a base CLFS system as it has additional dependencies) to help collect information about the memory usage of a program The network services library The Name Service Switch libraries, containing functions for resolving host names, user names, group names, aliases, services, protocols, etc. Contains profiling functions used to track the amount of CPU time spent in specific source code lines The POSIX threads library Contains functions for creating, sending, and interpreting packets to the Internet domain name servers Contains functions providing miscellaneous RPC services Contains functions providing most of the interfaces specified by the POSIX.1b Realtime Extension Contains functions useful for building debuggers for multi-threaded programs Contains code for “standard” functions used in many different Unix utilities

libBrokenLocale Used by programs, such as Mozilla, to solve broken locales

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10.8. Adjusting the Toolchain
Now we amend the GCC specs file so that it points to the new dynamic linker. A perl command accomplishes this: gcc -dumpspecs | \ perl -p -e 's@/tools/lib/ld@/lib/ld@g;' \ -e 's@\*startfile_prefix_spec:\n@$_/usr/lib/ @g;' > \ $(dirname $(gcc --print-libgcc-file-name))/specs It is a good idea to visually inspect the specs file to verify the intended change was actually made. Note that /lib is now the prefix of our dynamic linker.

Caution
It is imperative at this point to stop and ensure that the basic functions (compiling and linking) of the adjusted toolchain are working as expected. To do this, perform a sanity check: echo 'main(){}' > dummy.c gcc dummy.c readelf -l a.out | grep ': /lib' If everything is working correctly, there should be no errors, and the output of the last command will be: [Requesting program interpreter: /lib/ld-linux.so.2] Note that /lib is now the prefix of our dynamic linker. If the output does not appear as shown above or is not received at all, then something is seriously wrong. Investigate and retrace the steps to find out where the problem is and correct it. The most likely reason is that something went wrong with the specs file amendment above. Any issues will need to be resolved before continuing on with the process. Once everything is working correctly, clean up the test files: rm -v dummy.c a.out

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10.9. Binutils-2.18
The Binutils package contains a linker, an assembler, and other tools for handling object files.

10.9.1. Installation of Binutils
Verify that the PTYs are working properly inside the build environment. Check that everything is set up correctly by performing a simple test: expect -c "spawn ls" If the following message shows up, the environment is not set up for proper PTY operation: The system has no more ptys. Ask your system administrator to create more. This issue needs to be resolved before running the test suites for Binutils and GCC. The following patches merges all updates from the 2.18 Branch from the Binutils developers: patch -Np1 -i ../binutils-2.18-branch_update-3.patch The Binutils documentation recommends building Binutils outside of the source directory in a dedicated build directory: mkdir -v ../binutils-build cd ../binutils-build Prepare Binutils for compilation: ../binutils-2.18/configure --prefix=/usr \ --enable-shared Compile the package: make configure-host

Important
During make configure-host you may receive the following error message. It is safe to ignore. WARNING: `flex' is missing on your system. You should only need it if you modified a `.l' file. You may need the `Flex' package in order for those modifications to take effect. You can get `Flex' from any GNU archive site. make tooldir=/usr
The meaning of the make parameter:

tooldir=/usr Normally, the tooldir (the directory where the executables will ultimately be located) is set to $(exec_ prefix)/$(target_alias). Because this is a custom system, this target-specific directory in /usr is not required. 122

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Important
The test suite for Binutils is considered critical. Do not skip it under any circumstance. Test the results: make check Install the package: make tooldir=/usr install Install the libiberty header file that is needed by some packages: cp -v ../binutils-2.18/include/libiberty.h /usr/include

Short Descriptions
addr2line Translates program addresses to file names and line numbers; given an address and the name of an executable, it uses the debugging information in the executable to determine which source file and line number are associated with the address Creates, modifies, and extracts from archives An assembler that assembles the output of gcc into object files Used by the linker to de-mangle C++ and Java symbols and to keep overloaded functions from clashing Displays call graph profile data A linker that combines a number of object and archive files into a single file, relocating their data and tying up symbol references Lists the symbols occurring in a given object file Translates one type of object file into another Displays information about the given object file, with options controlling the particular information to display; the information shown is useful to programmers who are working on the compilation tools Generates an index of the contents of an archive and stores it in the archive; the index lists all of the symbols defined by archive members that are relocatable object files Displays information about ELF type binaries Lists the section sizes and the total size for the given object files Outputs, for each given file, the sequences of printable characters that are of at least the specified length (defaulting to four); for object files, it prints, by default, only the strings from the initializing and loading sections while for other types of files, it scans the entire file 123

libopcodes A library for dealing with opcodes—the “readable text” versions of instructions for the processor; it is used for building utilities like objdump.

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10.10. GCC-4.2.4
The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.

10.10.1. Installation of GCC
The following patch enables fixes compilation errors with the kernel: patch -Np1 -i ../gcc-4.2.4-PR31490-1.patch Apply a sed substitution that will suppress the installation of libiberty.a. The version of libiberty.a provided by Binutils will be used instead: sed -i 's/install_to_$(INSTALL_DEST) //' libiberty/Makefile.in GCC provides a gccbug script which detects at compile time whether mktemp is present, and hardcodes the result in a test. If mktemp is not found, the script will fall back to using less random names for temporary files. We will be installing mktemp later, so the following sed will simulate its presence: sed -i 's/@have_mktemp_command@/yes/' gcc/gccbug.in The GCC documentation recommends building GCC outside of the source directory in a dedicated build directory: mkdir -v ../gcc-build cd ../gcc-build Prepare GCC for compilation: ../gcc-4.2.4/configure --prefix=/usr \ --libexecdir=/usr/lib --enable-shared --enable-threads=posix \ --enable-__cxa_atexit --enable-c99 --enable-long-long \ --enable-clocale=gnu --enable-languages=c,c++ \ --disable-multilib --disable-libstdcxx-pch Compile the package: make bootstrap

Important
The test suite for GCC is considered critical. Do not skip it under any circumstance. Test the results, but do not stop at errors: make -k check The -k flag is used to make the test suite run through to completion and not stop at the first failure. The GCC test suite is very comprehensive and is almost guaranteed to generate a few failures. To receive a summary of the test suite results, run: ../gcc-4.2.4/contrib/test_summary For only the summaries, pipe the output through grep -A7 Summ. 125

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 A few unexpected failures cannot always be avoided. The GCC developers are usually aware of these issues, but have not resolved them yet. Install the package: make install Some packages expect the C preprocessor to be installed in the /lib directory. To support those packages, create this symlink: ln -sv ../usr/bin/cpp /lib Many packages use the name cc to call the C compiler. To satisfy those packages, create a symlink: ln -sv gcc /usr/bin/cc

Short Descriptions
cc cpp c++ g++ gcc gccbug gcov libgcc The C compiler The C preprocessor; it is used by the compiler to expand the #include, #define, and similar statements in the source files The C++ compiler The C++ compiler The C compiler A shell script used to help create useful bug reports A coverage testing tool; it is used to analyze programs to determine where optimizations will have the most effect Contains run-time support for gcc

libmudflap The libmudflap libraries are used by GCC for instrumenting pointer and array dereferencing operations. libstdc++ libsupc++ The standard C++ library Provides supporting routines for the C++ programming language

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10.11. Sed-4.1.5
The Sed package contains a stream editor.

10.11.1. Installation of Sed
Prepare Sed for compilation: ./configure --prefix=/usr --bindir=/bin --enable-html
The meaning of the new configure option:

--enable-html This option tells Sed to build and install its HTML documentation. Compile the package: make To test the results, issue: make check. Install the package: make install

10.11.2. Contents of Sed
Installed program: sed

Short Descriptions
sed Filters and transforms text files in a single pass

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10.12. E2fsprogs-1.40.4
The E2fsprogs package contains the utilities for handling the ext2 file system. It also supports the ext3 journaling file system.

10.12.1. Installation of E2fsprogs
The E2fsprogs documentation recommends that the package be built in a subdirectory of the source tree: mkdir -v build cd build Prepare E2fsprogs for compilation: ../configure --prefix=/usr --with-root-prefix="" \ --enable-elf-shlibs --disable-evms \ --with-cc=gcc
The meaning of the configure options:

--with-root-prefix="" Certain programs (such as the e2fsck program) are considered essential programs. When, for example, /usr is not mounted, these programs still need to be available. They belong in directories like /lib and /sbin. If this option is not passed to E2fsprogs' configure, the programs are installed into the /usr directory. --enable-elf-shlibs This creates the shared libraries which some programs in this package use. --disable-evms This disables the building of the Enterprise Volume Management System (EVMS) plugin. This plugin is not up-to-date with the latest EVMS internal interfaces and EVMS is not installed as part of a base CLFS system, so the plugin is not required. See the EVMS website at http://evms.sourceforge.net/ for more information regarding EVMS. Compile the package: make To test the results, issue: make check. Install the binaries, documentation and shared libraries: make install Install the static libraries and headers: make install-libs

Short Descriptions
badblocks blkid chattr compile_et debugfs dumpe2fs e2fsck e2image e2label filefrag findfs fsck fsck.ext2 fsck.ext3 logsave lsattr mk_cmds mke2fs mkfs.ext2 mkfs.ext3 mklost+found resize2fs tune2fs uuidd Searches a device (usually a disk partition) for bad blocks A command line utility to locate and print block device attributes Changes the attributes of files on an ext2 file system; it also changes ext3 file systems, the journaling version of ext2 file systems An error table compiler; it converts a table of error-code names and messages into a C source file suitable for use with the com_err library A file system debugger; it can be used to examine and change the state of an ext2 file system Prints the super block and blocks group information for the file system present on a given device Is used to check, and optionally repair ext2 file systems and ext3 file systems Is used to save critical ext2 file system data to a file Displays or changes the file system label on the ext2 file system present on a given device Reports on how badly fragmented a particular file might be Finds a file system by label or Universally Unique Identifier (UUID) Is used to check, and optionally repair, file systems By default checks ext2 file systems By default checks ext3 file systems Saves the output of a command in a log file Lists the attributes of files on a second extended file system Converts a table of command names and help messages into a C source file suitable for use with the libss subsystem library Creates an ext2 or ext3 file system on the given device By default creates ext2 file systems By default creates ext3 file systems Used to create a lost+found directory on an ext2 file system; it pre-allocates disk blocks to this directory to lighten the task of e2fsck Can be used to enlarge or shrink an ext2 file system Adjusts tunable file system parameters on an ext2 file system The uuidd daemon is used by the UUID library to generate universally unique identifiers (UUIDs), especially time-based UUID's in a secure and guaranteed-unique fashion, even in the face of large numbers of threads trying to grab UUID's running on different CPU's. Creates new UUIDs. Each new UUID can reasonably be considered unique among all UUIDs created, on the local system and on other systems, in the past and in the future Contains routines for device identification and token extraction The common error display routine Used by dumpe2fs, chattr, and lsattr Contains routines to enable user-level programs to manipulate an ext2 file system 129

uuidgen libblkid libcom_err libe2p libext2fs

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 libss libuuid Used by debugfs Contains routines for generating unique identifiers for objects that may be accessible beyond the local system

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10.13. Coreutils-6.9
The Coreutils package contains utilities for showing and setting the basic system characteristics.

10.13.1. Installation of Coreutils
Prevent Coreutils from installing binaries that will be installed by other packages: patch -Np1 -i ../coreutils-6.9-suppress_uptime_kill_su-1.patch A known issue with the uname program from this package is that the -p switch always returns unknown. The following patch fixes this behavior for all architectures: patch -Np1 -i ../coreutils-6.9-uname-1.patch The following command renames the internal implementation of futimens to gl_futimens as newer versions of Glibc provide an incompatible version: sed -i "s/futimens/gl_&/" $(grep -lr futimens *) Now prepare Coreutils for compilation: ./configure --prefix=/usr Compile the package: make The test suite of Coreutils makes several assumptions about the presence of system users and groups that are not valid within the minimal environment that exists at the moment. Therefore, additional items need to be set up before running the tests. Skip down to “Install the package” if not running the test suite. Create two dummy groups and a dummy user: echo "dummy1:x:1000:" >> /etc/group echo "dummy2:x:1001:dummy" >> /etc/group echo "dummy:x:1000:1000::/root:/bin/bash" >> /etc/passwd Now the test suite is ready to be run. First, run the tests that are meant to be run as user root: make NON_ROOT_USERNAME=dummy check-root Then run the remainder of the tests as the dummy user: src/su dummy -c "make RUN_EXPENSIVE_TESTS=yes check" When testing is complete, remove the dummy user and groups: sed -i '/dummy/d' /etc/passwd /etc/group Install the package: make install 131

Other Coreutils programs are used by some of the scripts in the CLFS-Bootscripts package. As /usr may not be available during the early stages of booting, those binaries need to be on the root partition: mv -v /usr/bin/{[,basename,head,install,nice} /bin mv -v /usr/bin/{readlink,sleep,sync,test,touch} /bin ln -svf ../../bin/install /usr/bin

Short Descriptions
base64 basename cat chgrp chmod chown chroot cksum comm cp csplit cut date dd df Base64 encode/decode data and print to standard output Strips any path and a given suffix from a file name Concatenates files to standard output Changes the group ownership of files and directories Changes the permissions of each file to the given mode; the mode can be either a symbolic representation of the changes to make or an octal number representing the new permissions Changes the user and/or group ownership of files and directories Runs a command with the specified directory as the / directory Prints the Cyclic Redundancy Check (CRC) checksum and the byte counts of each specified file Compares two sorted files, outputting in three columns the lines that are unique and the lines that are common Copies files Splits a given file into several new files, separating them according to given patterns or line numbers and outputting the byte count of each new file Prints sections of lines, selecting the parts according to given fields or positions Displays the current time in the given format, or sets the system date Copies a file using the given block size and count, while optionally performing conversions on it Reports the amount of disk space available (and used) on all mounted file systems, or only on the file systems holding the selected files 132

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 dir dircolors dirname du echo env expand expr factor false fmt fold groups head hostid hostname id install join link ln logname ls md5sum mkdir mkfifo mknod mv nice nl nohup od paste pathchk Lists the contents of each given directory (the same as the ls command) Outputs commands to set the LS_COLOR environment variable to change the color scheme used by ls Strips the non-directory suffix from a file name Reports the amount of disk space used by the current directory, by each of the given directories (including all subdirectories) or by each of the given files Displays the given strings Runs a command in a modified environment Converts tabs to spaces Evaluates expressions Prints the prime factors of all specified integer numbers Does nothing, unsuccessfully; it always exits with a status code indicating failure Reformats the paragraphs in the given files Wraps the lines in the given files Reports a user's group memberships Prints the first ten lines (or the given number of lines) of each given file Reports the numeric identifier (in hexadecimal) of the host Reports or sets the name of the host Reports the effective user ID, group ID, and group memberships of the current user or specified user Copies files while setting their permission modes and, if possible, their owner and group Joins the lines that have identical join fields from two separate files Creates a hard link with the given name to a file Makes hard links or soft (symbolic) links between files Reports the current user's login name Lists the contents of each given directory Reports or checks Message Digest 5 (MD5) checksums Creates directories with the given names Creates First-In, First-Outs (FIFOs), a “named pipe” in UNIX parlance, with the given names Creates device nodes with the given names; a device node is a character special file, a block special file, or a FIFO Moves or renames files or directories Runs a program with modified scheduling priority Numbers the lines from the given files Runs a command immune to hangups, with its output redirected to a log file Dumps files in octal and other formats Merges the given files, joining sequentially corresponding lines side by side, separated by tab characters Checks if file names are valid or portable 133

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 pinky pr printenv printf ptx pwd readlink rm rmdir seq sha1sum sha224sum sha256sum sha384sum sha512sum shred shuf sleep sort split stat stty sum sync tac tail tee test or [ touch tr true tsort tty uname Is a lightweight finger client; it reports some information about the given users Paginates and columnates files for printing Prints the environment Prints the given arguments according to the given format, much like the C printf function Produces a permuted index from the contents of the given files, with each keyword in its context Reports the name of the current working directory Reports the value of the given symbolic link Removes files or directories Removes directories if they are empty Prints a sequence of numbers within a given range and with a given increment Prints or checks 160-bit Secure Hash Algorithm 1 (SHA1) checksums Prints or checks SHA224 checksums Prints or checks SHA256 checksums Prints or checks SHA384 checksums Prints or checks SHA512 checksums Overwrites the given files repeatedly with complex patterns, making it difficult to recover the data Write a random permutation of the input lines to standard output or a file Pauses for the given amount of time Sorts the lines from the given files Splits the given file into pieces, by size or by number of lines Displays file or filesystem status Sets or reports terminal line settings Prints checksum and block counts for each given file Flushes file system buffers; it forces changed blocks to disk and updates the super block Concatenates the given files in reverse Prints the last ten lines (or the given number of lines) of each given file Reads from standard input while writing both to standard output and to the given files Compares values and checks file types Changes file timestamps, setting the access and modification times of the given files to the current time; files that do not exist are created with zero length Translates, squeezes, and deletes the given characters from standard input Does nothing, successfully; it always exits with a status code indicating success Performs a topological sort; it writes a completely ordered list according to the partial ordering in a given file Reports the file name of the terminal connected to standard input Reports system information 134

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 unexpand uniq unlink users vdir wc who whoami yes Converts spaces to tabs Discards all but one of successive identical lines Removes the given file Reports the names of the users currently logged on Is the same as ls -l Reports the number of lines, words, and bytes for each given file, as well as a total line when more than one file is given Reports who is logged on Reports the user name associated with the current effective user ID Repeatedly outputs “y” or a given string until killed

10.14.1. Installation of Iana-Etc
The following command converts the raw data provided by IANA into the correct formats for the /etc/protocols and /etc/services data files: make This package does not come with a test suite. Install the package: make install

Short Descriptions
/etc/protocols /etc/services Describes the various DARPA Internet protocols that are available from the TCP/IP subsystem Provides a mapping between friendly textual names for internet services, and their underlying assigned port numbers and protocol types

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10.15. M4-1.4.10
The M4 package contains a macro processor.

10.15.1. Installation of M4
Prepare M4 for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install

10.15.2. Contents of M4
Installed program: m4

Short Descriptions
m4 copies the given files while expanding the macros that they contain. These macros are either built-in or user-defined and can take any number of arguments. Besides performing macro expansion, m4 has built-in functions for including named files, running Unix commands, performing integer arithmetic, manipulating text, recursion, etc. The m4 program can be used either as a front-end to a compiler or as a macro processor in its own right.

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10.16. Bison-2.3
The Bison package contains a parser generator.

10.16.1. Installation of Bison
Prepare Bison for compilation: ./configure --prefix=/usr The configure system causes bison to be built without support for internationalization of error messages if a bison program is not already in $PATH. The following addition will correct this: echo '#define YYENABLE_NLS 1' >> config.h Compile the package: make To test the results, issue: make check. Install the package: make install

Short Descriptions
bison yacc liby.a Generates, from a series of rules, a program for analyzing the structure of text files; Bison is a replacement for Yacc (Yet Another Compiler Compiler) A wrapper for bison, meant for programs that still call yacc instead of bison; it calls bison with the -y option The Yacc library containing implementations of Yacc-compatible yyerror and main functions; this library is normally not very useful, but POSIX requires it

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10.17. Ncurses-5.6
The Ncurses package contains libraries for terminal-independent handling of character screens.

Short Descriptions
captoinfo clear Converts a termcap description into a terminfo description Clears the screen, if possible 139

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 infocmp infotocap ncurses5-config reset tack tic Compares or prints out terminfo descriptions Converts a terminfo description into a termcap description Provides configuration information for ncurses Reinitializes a terminal to its default values The terminfo action checker; it is mainly used to test the accuracy of an entry in the terminfo database The terminfo entry-description compiler that translates a terminfo file from source format into the binary format needed for the ncurses library routines. A terminfo file contains information on the capabilities of a certain terminal Lists all available terminal types, giving the primary name and description for each Makes the values of terminal-dependent capabilities available to the shell; it can also be used to reset or initialize a terminal or report its long name Can be used to initialize terminals A link to libncurses Contains functions to display text in many complex ways on a terminal screen; a good example of the use of these functions is the menu displayed during the kernel's make menuconfig Contains functions to implement forms Contains functions to implement menus Contains functions to implement panels

Short Descriptions
free kill pgrep pkill pmap ps pwdx skill slabtop snice sysctl tload top uptime vmstat w watch Reports the amount of free and used memory (both physical and swap memory) in the system Sends signals to processes Looks up processes based on their name and other attributes Signals processes based on their name and other attributes Reports the memory map of the given process Lists the current running processes Reports the current working directory of a process Sends signals to processes matching the given criteria Displays detailed kernel slab cache information in real time Changes the scheduling priority of processes matching the given criteria Modifies kernel parameters at run time Prints a graph of the current system load average Displays a list of the most CPU intensive processes; it provides an ongoing look at processor activity in real time Reports how long the system has been running, how many users are logged on, and the system load averages Reports virtual memory statistics, giving information about processes, memory, paging, block Input/Output (IO), traps, and CPU activity Shows which users are currently logged on, where, and since when Runs a given command repeatedly, displaying the first screen-full of its output; this allows a user to watch the output change over time 141

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 libproc Contains the functions used by most programs in this package

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10.19. Libtool-1.5.26
The Libtool package contains the GNU generic library support script. It wraps the complexity of using shared libraries in a consistent, portable interface.

10.19.1. Installation of Libtool
Prepare Libtool for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install

Short Descriptions
libtool libtoolize libltdl Provides generalized library-building support services Provides a standard way to add libtool support to a package Hides the various difficulties of dlopening libraries

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10.20. Flex-2.5.35
The Flex package contains a utility for generating programs that recognize patterns in text.

10.20.1. Installation of Flex
Prepare Flex for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install There are some packages that expect to find the lex library in /usr/lib. Create a symlink to account for this: ln -sv libfl.a /usr/lib/libl.a A few programs do not know about flex yet and try to run its predecessor, lex. To support those programs, create a wrapper script named lex that calls flex in lex emulation mode: cat > /usr/bin/lex << "EOF" #!/bin/sh # Begin /usr/bin/lex exec /usr/bin/flex -l "$@" # End /usr/bin/lex EOF chmod -v 755 /usr/bin/lex

Short Descriptions
flex lex libfl.a A tool for generating programs that recognize patterns in text; it allows for the versatility to specify the rules for pattern-finding, eradicating the need to develop a specialized program A script that runs flex in lex emulation mode The flex library

10.21.1. Installation of IPRoute2
The arpd binary included in this package is dependent on Berkeley DB. Because arpd is not a very common requirement on a base Linux system, remove the dependency on Berkeley DB by applying the sed command below. If the arpd binary is needed, instructions for compiling Berkeley DB can be found in the BLFS Book at http://cblfs. cross-lfs.org/index.php/Berkeley_DB. sed -i '/^TARGETS/s@arpd@@g' misc/Makefile Compile the package: make SBINDIR=/sbin
The meaning of the make option:

SBINDIR=/sbin This ensures that the IPRoute2 binaries will install into /sbin. This is the correct location according to the FHS, because some of the IPRoute2 binaries are used by the CLFS-Bootscripts package. This package does not come with a test suite. Install the package: make SBINDIR=/sbin install

Short Descriptions
ctstat ifcfg ifstat ip Connection status utility A shell script wrapper for the ip command Shows the interface statistics, including the amount of transmitted and received packets by interface The main executable. It has several different functions: ip link [device] allows users to look at the state of devices and to make changes ip addr allows users to look at addresses and their properties, add new addresses, and delete old ones ip neighbor allows users to look at neighbor bindings and their properties, add new neighbor entries, and delete old ones ip rule allows users to look at the routing policies and change them ip route allows users to look at the routing table and change routing table rules ip tunnel allows users to look at the IP tunnels and their properties, and change them ip maddr allows users to look at the multicast addresses and their properties, and change them ip mroute allows users to set, change, or delete the multicast routing ip monitor allows users to continously monitor the state of devices, addresses and routes 145

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 lnstat nstat routef routel rtacct rtmon rtpr rtstat ss tc Provides Linux network statistics. It is a generalized and more feature-complete replacement for the old rtstat program Shows network statistics A component of ip route. This is for flushing the routing tables A component of ip route. This is for listing the routing tables Displays the contents of /proc/net/rt_acct Route monitoring utility Converts the output of ip -o back into a readable form Route status utility Similar to the netstat command; shows active connections Traffic Controlling Executable; this is for Quality Of Service (QOS) and Class Of Service (COS) implementations tc qdisc allows users to setup the queueing discipline tc class allows users to setup classes based on the queuing discipline scheduling tc estimator allows users to estimate the network flow into a network tc filter allows users to setup the QOS/COS packet filtering tc policy allows users to setup the QOS/COS policies

10.22.1. Installation of Perl
The following patch causes makedepend.sh to also remove <command-line> as well as <command line>: patch -Np1 -i ../perl-5.8.8-gcc42_fix-1.patch The following patch prevents perl from including asm/page.h which will no longer be available in headers provided by kernel 2.6.25 and forward: patch -Np1 -i ../perl-5.8.8-no_page_h-1.patch The following patch fixes known vulnerabilities in perl: patch -Np1 -i ../perl-5.8.8-security_fixes-1.patch The following sed causes DynaLoader.a to be built with -fPIC so it can be linked into a shared library later: sed -i -e "s@pldlflags=''@pldlflags=\"\$cccdlflags\"@g" \ -e "s@static_target='static'@static_target='static_pic'@g" Makefile.SH

Note
If you are following the boot method you will need to enable the loopback device as well as set a hostname for some of the tests: ip link set lo up hostname clfs Before starting to configure, create a basic /etc/hosts file which will be referenced by one of Perl's configuration files as well as used by the testsuite: echo "127.0.0.1 localhost $(hostname)" > /etc/hosts To have full control over the way Perl is set up, you can run the interactive Configure script and hand-pick the way this package is built. If you prefer instead to use the defaults that Perl auto-detects, prepare Perl for compilation with: CC=gcc ./configure.gnu --prefix=/usr \ -Dman1dir=/usr/share/man/man1 \ -Dman3dir=/usr/share/man/man3 \ -Dpager="/bin/less -isR" \ -Dusethreads
The meaning of the configure option:

-Dpager="/bin/less -isR" This corrects an error in the way that perldoc invokes the less program. -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 Since Groff is not installed yet, configure.gnu thinks that we do not want man pages for Perl. Issuing these parameters overrides this decision. 147

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 -Dusethreads This tells Perl to use threads. Compile the package: make To test the results, issue: make test. Install the package: make install

Short Descriptions
a2p c2ph cpan dprofpp enc2xs find2perl h2ph h2xs libnetcfg instmodsh perl perl5.8.8 perlbug perlcc perldoc perlivp piconv pl2pm Translates awk to Perl Dumps C structures as generated from cc -g -S Shell script that provides a command interface to CPAN.pm Displays Perl profile data Builds a Perl extension for the Encode module from either Unicode Character Mappings or Tcl Encoding Files Translates find commands to Perl Converts .h C header files to .ph Perl header files Converts .h C header files to Perl extensions Can be used to configure the libnet A shell script for examining installed Perl modules, and can even create a tarball from an installed module Combines some of the best features of C, sed, awk and sh into a single swiss-army-knife language A hard link to perl Used to generate bug reports about Perl, or the modules that come with it, and mail them Generates executables from Perl programs Displays a piece of documentation in pod format that is embedded in the Perl installation tree or in a Perl script The Perl Installation Verification Procedure; it can be used to verify that Perl and its libraries have been installed correctly A Perl version of the character encoding converter iconv A rough tool for converting Perl4 .pl files to Perl5 .pm modules 148

10.23. Readline-5.2
The Readline package is a set of libraries that offers command-line editing and history capabilities.

10.23.1. Installation of Readline
The following patch contains updates from the maintainer. The maintainer of Readline only releases these patches to fix serious issues: patch -Np1 -i ../readline-5.2-fixes-4.patch Prepare Readline for compilation: ./configure --prefix=/usr --libdir=/lib Compile the package: make SHLIB_XLDFLAGS=-lncurses
The meaning of the make option:

SHLIB_XLDFLAGS=-lncurses This option forces Readline to link against the libncurses library. This package does not come with a test suite. Install the package: make install Give Readline's dynamic libraries more appropriate permissions: chmod -v 755 /lib/lib{readline,history}.so* Now move the static libraries to a more appropriate location: mv -v /lib/lib{readline,history}.a /usr/lib Next, remove the .so files in /lib and relink them into /usr/lib. rm -v /lib/lib{readline,history}.so ln -svf ../../lib/libreadline.so.5 /usr/lib/libreadline.so ln -svf ../../lib/libhistory.so.5 /usr/lib/libhistory.so

Short Descriptions
libhistory Provides a consistent user interface for recalling lines of history libreadline Aids in the consistency of user interface across discrete programs that need to provide a command line interface

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10.24. Zlib-1.2.3
The Zlib package contains compression and decompression routines used by some programs.

10.24.1. Installation of Zlib
This patch will add -fPIC to our build and allow us to build a static and shared library at the same time: patch -Np1 -i ../zlib-1.2.3-fPIC-1.patch Prepare Zlib for compilation: ./configure --prefix=/usr --shared Compile the package: make To test the results, issue: make check. Install the package: make install The previous command installed two .so files into /usr/lib. We will move it into /lib and then relink it to /usr/lib: mv -v /usr/lib/libz.so.* /lib ln -svf ../../lib/libz.so.1 /usr/lib/libz.so Now we fix the permissions on the static library: chmod -v 644 /usr/lib/libz.a

10.24.2. Contents of Zlib
Installed libraries: libz.[a,so]

Short Descriptions
libz Contains compression and decompression functions used by some programs

10.25.1. Installation of Autoconf
Prepare Autoconf for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. 6 tests are skipped that use Automake. For full test coverage, Autoconf can be re-tested after Automake has been installed. Install the package: make install

Short Descriptions
autoconf Produces shell scripts that automatically configure software source code packages to adapt to many kinds of Unix-like systems. The configuration scripts it produces are independent—running them does not require the autoconf program. A tool for creating template files of C #define statements for configure to use A wrapper for the M4 macro processor Automatically runs autoconf, autoheader, aclocal, automake, gettextize, and libtoolize in the correct order to save time when changes are made to autoconf and automake template files Helps to create a configure.in file for a software package; it examines the source files in a directory tree, searching them for common portability issues, and creates a configure.scan file that serves as as a preliminary configure.in file for the package Modifies a configure.in file that still calls autoconf macros by their old names to use the current macro names Helps when writing configure.in files for a software package; it prints the identifiers that the package uses in C preprocessor conditionals. If a package has already been set up to have some portability, this program can help determine what configure needs to check for. It can also fill in gaps in a configure.in file generated by autoscan

autoheader autom4te autoreconf autoscan

autoupdate ifnames

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10.26. Automake-1.10.1
The Automake package contains programs for generating Makefiles for use with Autoconf.

10.26.1. Installation of Automake
Prepare Automake for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install

Short Descriptions
acinstall aclocal aclocal-1.10 automake A script that installs aclocal-style M4 files Generates aclocal.m4 files based on the contents of configure.in files A hard link to aclocal A tool for automatically generating Makefile.in files from Makefile.am files. To create all the Makefile.in files for a package, run this program in the top-level directory. By scanning the configure.in file, it automatically finds each appropriate Makefile.am file and generates the corresponding Makefile.in file A hard link to automake A wrapper for compilers A script that attempts to guess the canonical triplet for the given build, host, or target architecture A configuration validation subroutine script A script for compiling a program so that dependency information is generated in addition to the desired output Byte-compiles Emacs Lisp code A script that installs a program, script, or data file A script that prints the modification time of a file or directory A script acting as a common stub for missing GNU programs during an installation A script that creates a directory tree 153

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 py-compile symlink-tree ylwrap Compiles a Python program A script to create a symlink tree of a directory tree A wrapper for lex and yacc

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10.27. Bash-3.2
The Bash package contains the Bourne-Again SHell.

10.27.1. Installation of Bash
If you downloaded the Bash documentation tarball and wish to install HTML documentation, issue the following commands: tar -xvf ../bash-doc-3.2.tar.gz The following patch contains updates from the maintainer. The maintainer of Bash only releases these patches to fix serious issues: patch -Np1 -i ../bash-3.2-fixes-8.patch Prepare Bash for compilation: ./configure --prefix=/usr --bindir=/bin \ --without-bash-malloc --with-installed-readline
The meaning of the configure option:

--with-installed-readline This option tells Bash to use the readline library that is already installed on the system rather than using its own readline version. Compile the package: make To test the results, issue: make tests. Install the package: make htmldir=/usr/share/doc/bash-3.2 install Run the newly compiled bash program (replacing the one that is currently being executed): exec /bin/bash --login +h

Note
The parameters used make the bash process an interactive login shell and continue to disable hashing so that new programs are found as they become available.

Short Descriptions
bash A widely-used command interpreter; it performs many types of expansions and substitutions on a given command line before executing it, thus making this interpreter a powerful tool 155

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 bashbug sh A shell script to help the user compose and mail standard formatted bug reports concerning bash A symlink to the bash program; when invoked as sh, bash tries to mimic the startup behavior of historical versions of sh as closely as possible, while conforming to the POSIX standard as well

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10.28. Bzip2-1.0.4
The Bzip2 package contains programs for compressing and decompressing files. Compressing text files with bzip2 yields a much better compression percentage than with the traditional gzip.

10.28.1. Installation of Bzip2
The Bzip2 package does not contain a configure script. Compile it with: make -f Makefile-libbz2_so make clean The -f flag will cause Bzip2 to be built using a different Makefile file, in this case the Makefile-libbz2_ so file, which creates a dynamic libbz2.so library and links the Bzip2 utilities against it. Recompile the package using a non-shared library and test it: make Install the programs: make PREFIX=/usr install Install the shared bzip2 binary into the /bin directory, make some necessary symbolic links, and clean up: cp cp ln rm ln ln -v bzip2-shared /bin/bzip2 -av libbz2.so* /lib -sv ../../lib/libbz2.so.1.0 /usr/lib/libbz2.so -v /usr/bin/{bunzip2,bzcat,bzip2} -sv bzip2 /bin/bunzip2 -sv bzip2 /bin/bzcat

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 bzip2 Compresses files using the Burrows-Wheeler block sorting text compression algorithm with Huffman coding; the compression rate is better than that achieved by more conventional compressors using “Lempel-Ziv” algorithms, like gzip Tries to recover data from damaged bzipped files Runs less on bzipped files Runs more on bzipped files The library implementing lossless, block-sorting data compression, using the Burrows-Wheeler algorithm

bzip2recover bzless bzmore libbz2*

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10.29. Diffutils-2.8.7
The Diffutils package contains programs that show the differences between files or directories.

10.29.1. Installation of Diffutils
Prepare Diffutils for compilation: ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make install

Short Descriptions
cmp diff diff3 sdiff Compares two files and reports whether or in which bytes they differ Compares two files or directories and reports which lines in the files differ Compares three files line by line Merges two files and interactively outputs the results

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10.30. File-4.23
The File package contains a utility for determining the type of a given file or files.

10.30.1. Installation of File
Prepare File for compilation: ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make install

Short Descriptions
file Tries to classify each given file; it does this by performing several tests—file system tests, magic number tests, and language tests

libmagic Contains routines for magic number recognition, used by the file program

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10.31. Findutils-4.2.32
The Findutils package contains programs to find files. These programs are provided to recursively search through a directory tree and to create, maintain, and search a database (often faster than the recursive find, but unreliable if the database has not been recently updated).

--localstatedir This option changes the location of the locate database to be in /var/lib/locate, which is FHS-compliant. Compile the package: make To test the results, issue: make check. Install the package: make install The find program is used by some of the scripts in the CLFS-Bootscripts package. As /usr may not be available during the early stages of booting, the find binary needs to be on the root partition: mv -v /usr/bin/find /bin The updatedb script needs to be modified to point to the new location for find: sed -i 's@find:=${BINDIR}@find:=/bin@' /usr/bin/updatedb

Short Descriptions
bigram code find frcode locate updatedb Was formerly used to produce locate databases Was formerly used to produce locate databases; it is the ancestor of frcode. Searches given directory trees for files matching the specified criteria Is called by updatedb to compress the list of file names; it uses front-compression, reducing the database size by a factor of four to five. Searches through a database of file names and reports the names that contain a given string or match a given pattern Updates the locate database; it scans the entire file system (including other file systems that are currently mounted, unless told not to) and puts every file name it finds into the database 161

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 xargs Can be used to apply a given command to a list of files

10.32.1. Installation of Gawk
Prepare Gawk for compilation: ./configure --prefix=/usr --libexecdir=/usr/lib Now fix an issue that will cause the Gettext testsuite to fail: echo '#define HAVE_LC_MESSAGES 1' >> config.h Compile the package: make To test the results, issue: make check. Install the package: make install

Short Descriptions
awk gawk gawk-3.1.6 grcat igawk pgawk pgawk-3.1.6 pwcat A link to gawk A program for manipulating text files; it is the GNU implementation of awk A hard link to gawk Dumps the group database /etc/group Gives gawk the ability to include files The profiling version of gawk Hard link to pgawk Dumps the password database /etc/passwd

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10.33. Gettext-0.17
The Gettext package contains utilities for internationalization and localization. These allow programs to be compiled with NLS (Native Language Support), enabling them to output messages in the user's native language.

10.33.1. Installation of Gettext
Prepare Gettext for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install

Short Descriptions
autopoint envsubst gettext gettext.sh gettextize hostname msgattrib msgcat msgcmp msgcomm msgconv msgen msgexec msgfilter Copies standard Gettext infrastructure files into a source package Substitutes environment variables in shell format strings Translates a natural language message into the user's language by looking up the translation in a message catalog Primarily serves as a shell function library for gettext Copies all standard Gettext files into the given top-level directory of a package to begin internationalizing it Displays a network hostname in various forms Filters the messages of a translation catalog according to their attributes and manipulates the attributes Concatenates and merges the given .po files Compares two .po files to check that both contain the same set of msgid strings Finds the messages that are common to to the given .po files Converts a translation catalog to a different character encoding Creates an English translation catalog Applies a command to all translations of a translation catalog Applies a filter to all translations of a translation catalog 164

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 msgfmt msggrep msginit msgmerge msgunfmt msguniq ngettext recode-sr-latin xgettext libasprintf libgettextlib libgettextpo Generates a binary message catalog from a translation catalog Extracts all messages of a translation catalog that match a given pattern or belong to some given source files Creates a new .po file, initializing the meta information with values from the user's environment Combines two raw translations into a single file Decompiles a binary message catalog into raw translation text Unifies duplicate translations in a translation catalog Displays native language translations of a textual message whose grammatical form depends on a number Recode Serbian text from Cyrillic to Latin script. Extracts the translatable message lines from the given source files to make the first translation template defines the autosprintf class, which makes C formatted output routines usable in C++ programs, for use with the <string> strings and the <iostream> streams a private library containing common routines used by the various Gettext programs; these are not intended for general use Used to write specialized programs that process .po files; this library is used when the standard applications shipped with Gettext (such as msgcomm, msgcmp, msgattrib, and msgen) will not suffice A private library containing common routines used by the various Gettext programs; these are not intended for general use

10.35.1. Installation of Groff
Groff expects the environment variable PAGE to contain the default paper size. For users in the United States, PAGE=letter is appropriate. Elsewhere, PAGE=A4 may be more suitable. Prepare Groff for compilation: PAGE=[paper_size] ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make install Some documentation programs, such as xman, will not work properly without the following symlinks: ln -sv soelim /usr/bin/zsoelim ln -sv eqn /usr/bin/geqn ln -sv tbl /usr/bin/gtbl

Short Descriptions
addftinfo afmtodit eqn eqn2graph gdiffmk geqn grap2graph grn grodvi Reads a troff font file and adds some additional font-metric information that is used by the groff system Creates a font file for use with groff and grops Compiles descriptions of equations embedded within troff input files into commands that are understood by troff Converts a troff EQN (equation) into a cropped image Marks differences between groff/nroff/troff files A link to eqn Converts a grap diagram into a cropped bitmap image A groff preprocessor for gremlin files A driver for groff that produces TeX dvi format 167

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 groff groffer grog grolbp grolj4 grops grotty gtbl hpftodit indxbib lkbib lookbib A front-end to the groff document formatting system; normally, it runs the troff program and a post-processor appropriate for the selected device Displays groff files and man pages on X and tty terminals Reads files and guesses which of the groff options -e, -man, -me, -mm, -ms, -p, -s, and -t are required for printing files, and reports the groff command including those options Is a groff driver for Canon CAPSL printers (LBP-4 and LBP-8 series laser printers) Is a driver for groff that produces output in PCL5 format suitable for an HP LaserJet 4 printer Translates the output of GNU troff to PostScript Translates the output of GNU troff into a form suitable for typewriter-like devices A link to tbl Creates a font file for use with groff -Tlj4 from an HP-tagged font metric file Creates an inverted index for the bibliographic databases with a specified file for use with refer, lookbib, and lkbib Searches bibliographic databases for references that contain specified keys and reports any references found Prints a prompt on the standard error (unless the standard input is not a terminal), reads a line containing a set of keywords from the standard input, searches the bibliographic databases in a specified file for references containing those keywords, prints any references found on the standard output, and repeats this process until the end of input A simple preprocessor for groff Formats equations for American Standard Code for Information Interchange (ASCII) output A script that emulates the nroff command using groff Creates pdf documents using groff Translates a PostScript font in .pfb format to ASCII Compiles descriptions of pictures embedded within troff or TeX input files into commands understood by TeX or troff Converts a PIC diagram into a cropped image Translates the output of GNU troff to HTML Translates the output of GNU troff to HTML Copies the contents of a file to the standard output, except that lines between .[ and .] are interpreted as citations, and lines between .R1 and .R2 are interpreted as commands for how citations are to be processed Reads files and replaces lines of the form .so file by the contents of the mentioned file Compiles descriptions of tables embedded within troff input files into commands that are understood by troff Creates a font file for use with groff -Tdvi Is highly compatible with Unix troff; it should usually be invoked using the groff command, which will also run preprocessors and post-processors in the appropriate order and with the appropriate options 168

10.36.1. Installation of Gzip
The following command renames the internal implementation of futimens to gl_futimens as newer versions of Glibc provide an incompatible version: sed -i "s/futimens/gl_&/" $(grep -lr futimens *) Prepare Gzip for compilation: ./configure --prefix=/usr --bindir=/bin Compile the package: make To test the results, issue: make check. Install the package: make install Now we will move some of utilities to /usr/bin to meet FHS compliance: mv -v /bin/z{egrep,cmp,diff,fgrep,force,grep,less,more,new} /usr/bin

10.37.1. Installation of Inetutils
Not all programs that come with Inetutils will be installed. However, the Inetutils build system will insist on installing all the man pages anyway. The following patch will correct this situation: patch -Np1 -i ../inetutils-1.5-no_server_man_pages-2.patch Prepare Inetutils for compilation: ./configure --prefix=/usr --libexecdir=/usr/sbin \ --sysconfdir=/etc --localstatedir=/var \ --disable-logger --disable-syslogd \ --disable-whois --disable-servers
The meaning of the configure options:

--disable-logger This option prevents Inetutils from installing the logger program, which is used by scripts to pass messages to the System Log Daemon. Do not install it because Util-linux-ng installs a better version later. --disable-syslogd This option prevents Inetutils from installing the System Log Daemon, which is installed with the Sysklogd package. --disable-whois This option disables the building of the Inetutils whois client, which is out of date. Instructions for a better whois client are in the CBLFS book. --disable-servers This disables the installation of the various network servers included as part of the Inetutils package. These servers are deemed not appropriate in a basic CLFS system. Compile the package: make This package does not come with a test suite. Install the package: make install Move the ping and ping6 programs to their FHS-compliant place: mv -v /usr/bin/ping{,6} /bin

Short Descriptions
ftp ifconfig ping ping6 rcp rlogin rsh talk telnet tftp Is the file transfer protocol program Utility for configuring network interfaces Sends echo-request packets and reports how long the replies take. This is the IPV4 version Sends echo-request packets and reports how long the replies take. This is the IPV6 version Performs remote file copy Performs remote login Runs a remote shell Is used to chat with another user An interface to the TELNET protocol A trivial file transfer program

10.38.1. Installation of Kbd
Prepare Kbd for compilation: ./configure --datadir=/lib/kbd
The meaning of the configure options:

--datadir This option places the Kbd data and keymap files into /lib/kbd, as they are used by some of the scripts in the CLFS-Bootscripts package and must be on the root partition. Compile the package: make This package does not come with a test suite. Install the package: make install Some of the programs from Kbd are used by scripts in the CLFS-Bootscripts package. As /usr may not be available during the early stages of booting, those binaries need to be on the root partition: mv -v /usr/bin/{kbd_mode,openvt,setfont} /bin

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 mapscrn openvt psfaddtable psfgettable psfstriptable psfxtable resizecons setfont setkeycodes setleds setmetamode showconsolefont showkey unicode_start unicode_stop An obsolete program that used to load a user-defined output character mapping table into the console driver; this is now done by setfont Starts a program on a new virtual terminal (VT) A link to psfxtable A link to psfxtable A link to psfxtable Handle Unicode character tables for console fonts Changes the kernel idea of the console size Changes the Enhanced Graphic Adapter (EGA) and Video Graphics Array (VGA) fonts on the console Loads kernel scancode-to-keycode mapping table entries; this is useful if there are unusual keys on the keyboard Sets the keyboard flags and Light Emitting Diodes (LEDs) Defines the keyboard meta-key handling Shows the current EGA/VGA console screen font Reports the scancodes, keycodes, and ASCII codes of the keys pressed on the keyboard Puts the keyboard and console in UNICODE mode. Never use it on CLFS, because applications are not configured to support UNICODE. Reverts keyboard and console from UNICODE mode

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10.39. Less-418
The Less package contains a text file viewer.

10.39.1. Installation of Less
Prepare Less for compilation: ./configure --prefix=/usr --sysconfdir=/etc
The meaning of the configure option:

--sysconfdir=/etc This option tells the programs created by the package to look in /etc for the configuration files. Compile the package: make This package does not come with a test suite. Install the package: make install Move less to /bin: mv -v /usr/bin/less /bin

10.39.2. Contents of Less
Installed programs: less, lessecho, and lesskey

Short Descriptions
less lessecho lesskey A file viewer or pager; it displays the contents of the given file, letting the user scroll, find strings, and jump to marks Needed to expand meta-characters, such as * and ?, in filenames on Unix systems Used to specify the key bindings for less

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10.40. Make-3.81
The Make package contains a program for compiling packages.

10.40.1. Installation of Make
Prepare Make for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install

10.40.2. Contents of Make
Installed program: make

Short Descriptions
make Automatically determines which pieces of a package need to be (re)compiled and then issues the relevant commands

10.41.1. Installation of Man
A few adjustments need to be made to the sources of Man. First, a sed substitution is needed to add the -R switch to the PAGER variable so that escape sequences are properly handled by Less: sed -i 's@-is@&R@g' configure Another couple of sed substitutions comment out the “MANPATH /usr/man” and “MANPATH /usr/local/man” lines in the man.conf file to prevent redundant results when using programs such as whatis: sed -i 's@MANPATH./usr/man@#&@g' src/man.conf.in sed -i 's@MANPATH./usr/local/man@#&@g' src/man.conf.in Prepare Man for compilation: ./configure -confdir=/etc
The meaning of the configure options:

-confdir=/etc This tells the man program to look for the man.conf configuration file in the /etc directory. Compile the package: make This package does not come with a test suite. Install the package: make install

Note
If you will be working on a terminal that does not support text attributes such as color and bold, you can disable Select Graphic Rendition (SGR) escape sequences by editing the man.conf file and adding the -c option to the NROFF variable. If you use multiple terminal types for one computer it may be better to selectively add the GROFF_NO_SGR environment variable for the terminals that do not support SGR. If the character set of the locale uses 8-bit characters, search for the line beginning with “NROFF” in /etc/man. conf, and verify that it matches the following: NROFF /usr/bin/nroff -Tlatin1 -mandoc Note that “latin1” should be used even if it is not the character set of the locale. The reason is that, according to the specification, groff has no means of typesetting characters outside International Organization for Standards (ISO) 8859-1 without some strange escape codes. When formatting man pages, groff thinks that they are in the ISO 8859-1 178

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 encoding and this -Tlatin1 switch tells groff to use the same encoding for output. Since groff does no recoding of input characters, the f ormatted result is really in the same encoding as input, and therefore it is usable as the input for a pager. This does not solve the problem of a non-working man2dvi program for localized man pages in non-ISO 8859-1 locales. Also, it does not work with multibyte character sets. The first problem does not currently have a solution. The second issue is not of concern because the CLFS installation does not support multibyte character sets.

Short Descriptions
apropos makewhatis man man2dvi man2html whatis Searches the whatis database and displays the short descriptions of system commands that contain a given string Builds the whatis database; it reads all the man pages in the MANPATH and writes the name and a short description in the whatis database for each page Formats and displays the requested on-line man page Converts a man page into dvi format Converts a man page into HTML Searches the whatis database and displays the short descriptions of system commands that contain the given keyword as a separate word

10.42.1. Installation of Mktemp
Many scripts still use the deprecated tempfile program, which has functionality similar to mktemp. Patch Mktemp to include a tempfile wrapper: patch -Np1 -i ../mktemp-1.5-add_tempfile-3.patch Prepare Mktemp for compilation: ./configure --prefix=/usr --with-libc
The meaning of the configure option:

--with-libc This causes the mktemp program to use the mkstemp and mkdtemp functions from the system C library. Compile the package: make This package does not come with a test suite. Install the package: make install make install-tempfile

10.42.2. Contents of Mktemp
Installed programs: mktemp and tempfile

Short Descriptions
mktemp tempfile Creates temporary files in a secure manner; it is used in scripts Creates temporary files in a less secure manner than mktemp; it is installed for backwards-compatibility

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10.43. Module-Init-Tools-3.4
The Module-Init-Tools package contains programs for handling kernel modules in Linux kernels greater than or equal to version 2.5.47.

10.43.1. Installation of Module-Init-Tools
The tarball only contains sgml source for the manual pages. The following patch contains the result of processing this through docbook2man which we do not build as part of a basic clfs install : patch -Np1 -i ../module-init-tools-3.4-manpages-1.patch Issue the following commands to perform the tests

Note
note that the make clean command is required to clean up the source tree, otherwise the code built for testing will be installed, and the test version of modprobe does not function outside the test environment. ./configure && make check && make clean Prepare Module-Init-Tools for compilation: ./configure --prefix=/ --enable-zlib
The meaning of the configure options:

--enable-zlib This allows the Module-Init-Tools package to handle compressed kernel modules. Compile the package: make Install the package: make INSTALL=install install
The meaning of the make install parameter:

INSTALL=install Normally, make install will not install the binaries if they already exist. This option overrides that behavior by calling install instead of using the default wrapper script.

Short Descriptions
depmod Creates a dependency file based on the symbols it finds in the existing set of modules; this dependency file is used by modprobe to automatically load the required modules 181

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 generate-modprobe.conf insmod insmod.static lsmod modinfo modprobe rmmod Creates a modprobe.conf file from an existing 2.2 or 2.4 module setup Installs a loadable module in the running kernel A statically compiled version of insmod Lists currently loaded modules Examines an object file associated with a kernel module and displays any information that it can glean Uses a dependency file, created by depmod, to automatically load relevant modules Unloads modules from the running kernel

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10.44. Patch-2.5.9
The Patch package contains a program for modifying or creating files by applying a “patch” file typically created by the diff program.

10.44.1. Installation of Patch
Prepare Patch for compilation: ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make install

10.44.2. Contents of Patch
Installed program: patch

Short Descriptions
patch Modifies files according to a patch file. A patch file is normally a difference listing created with the diff program. By applying these differences to the original files, patch creates the patched versions.

--exec-prefix="" This ensures that the Psmisc binaries will install into /bin instead of /usr/bin. This is the correct location according to the FHS, because some of the Psmisc binaries are used by the CLFS-Bootscripts package. Compile the package: make This package does not come with a test suite. Install the package: make install There is no reason for the pstree and pstree.x11 programs to reside in /bin. Therefore, move them to /usr/bin: mv -v /bin/pstree* /usr/bin By default, Psmisc's pidof program is not installed. This usually is not a problem because it is installed later in the Sysvinit package, which provides a better pidof program. If Sysvinit will not be used for a particular system, complete the installation of Psmisc by creating the following symlink: ln -sv killall /bin/pidof

Short Descriptions
fuser killall oldfuser pstree pstree.x11 Reports the Process IDs (PIDs) of processes that use the given files or file systems Kills processes by name; it sends a signal to all processes running any of the given commands Reports the Process IDs (PIDs) of processes that use the given files or file systems Displays running processes as a tree Same as pstree, except that it waits for confirmation before exiting

10.46.1. Installation of Shadow
Note
If you would like to enforce the use of strong passwords, refer to http://cblfs.cross-lfs.org/index. php/Cracklib for installing Cracklib prior to building Shadow. Then add --with-libcrack to the configure command below. Prepare Shadow for compilation: ./configure --libdir=/lib --sysconfdir=/etc --enable-shared \ --without-libpam --without-audit --without-selinux The meaning of the configure options: --sysconfdir=/etc Tells Shadow to install its configuration files into /etc, rather than /usr/etc. --without-libpam Support for Linux-PAM is enabled by default in Shadow, however PAM is not installed on a base CLFS system, so this switch disables PAM support in Shadow. For instructions to install PAM and link Shadow to it, you can look at http://cblfs.cross-lfs.org/index.php/Linux-PAM. --without-audit Support for auditing is enabled by default, but a library that it needs is not installed in a base CLFS system. This switch disables auditing support. --without-selinux Support for selinux is enabled by default, but selinux is not built in a base CLFS system and configure will fail without this switch. Disable the installation of the groups program and its man pages, as Coreutils provides a better version: sed -i 's/groups$(EXEEXT) //' src/Makefile find man -name Makefile -exec sed -i '/groups.1.xml/d' '{}' \; find man -name Makefile -exec sed -i 's/groups.1 //' '{}' \; Compile the package: make This package does not come with a test suite. Install the package: make install 185

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Instead of using the default crypt method, use the more secure MD5 method of password encryption, which also allows passwords longer than 8 characters. It is also necessary to change the obsolete /var/spool/mail location for user mailboxes that Shadow uses by default to the /var/mail location used currently. Use the following sed command to make these changes to the appropriate configuration file: sed -i /etc/login.defs \ -e 's@#MD5_CRYPT_ENAB.no@MD5_CRYPT_ENAB yes@' \ -e 's@/var/spool/mail@/var/mail@'

Note
If you built Shadow with Cracklib support, execute this sed to correct the path to the Cracklib dictionary: sed -i 's@DICTPATH.*@DICTPATH\t/lib/cracklib/pw_dict@' /etc/login.defs Move a misplaced program to its proper location: mv -v /usr/bin/passwd /bin

10.46.2. Configuring Shadow
This package contains utilities to add, modify, and delete users and groups; set and change their passwords; and perform other administrative tasks. For a full explanation of what password shadowing means, see the doc/HOWTO file within the unpacked source tree. If using Shadow support, keep in mind that programs which need to verify passwords (display managers, FTP programs, pop3 daemons, etc.) must be Shadow-compliant. That is, they need to be able to work with shadowed passwords. To enable shadowed passwords, run the following command: pwconv To enable shadowed group passwords, run: grpconv To view or change the default settings for new user accounts that you create, you can edit /etc/default/useradd. See man useradd or http://cblfs.cross-lfs.org/index.php/Configuring_for_Adding_ Users for more information.

10.46.3. Setting the root password
Choose a password for user root and set it by running: passwd root

Short Descriptions
chage chfn chgpasswd chpasswd chsh expiry faillog gpasswd groupadd groupdel groupmod grpck grpconv grpunconv lastlog login logoutd newgrp newusers nologin passwd pwck pwconv pwunconv sg su useradd userdel usermod vigr vipw Used to change the maximum number of days between obligatory password changes Used to change a user's full name and other information Used to update group passwords in batch mode Used to update the passwords of an entire series of user accounts Used to change a user's default login shell Checks and enforces the current password expiration policy Is used to examine the log of login failures, to set a maximum number of failures before an account is blocked, or to reset the failure count Is used to add and delete members and administrators to groups Creates a group with the given name Deletes the group with the given name Is used to modify the given group's name or GID Verifies the integrity of the group files /etc/group and /etc/gshadow Creates or updates the shadow group file from the normal group file Updates /etc/group from /etc/gshadow and then deletes the latter Reports the most recent login of all users or of a given user Is used by the system to let users sign on Is a daemon used to enforce restrictions on log-on time and ports Is used to change the current GID during a login session Is used to create or update an entire series of user accounts Displays a message that an account is not available. Designed to be used as the default shell for accounts that have been disabled Is used to change the password for a user or group account Verifies the integrity of the password files /etc/passwd and /etc/shadow Creates or updates the shadow password file from the normal password file Updates /etc/passwd from /etc/shadow and then deletes the latter Executes a given command while the user's GID is set to that of the given group Runs a shell with substitute user and group IDs Creates a new user with the given name, or updates the default new-user information Deletes the given user account Is used to modify the given user's login name, User Identification (UID), shell, initial group, home directory, etc. Edits the /etc/group or /etc/gshadow files Edits the /etc/passwd or /etc/shadow files

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10.47. Sysklogd-1.5
The Sysklogd package contains programs for logging system messages, such as those given by the kernel when unusual things happen.

10.47.1. Installation of Sysklogd
Compile the package: make This package does not come with a test suite. Install the package: make install

Short Descriptions
klogd syslogd A system daemon for intercepting and logging kernel messages Logs the messages that system programs offer for logging. Every logged message contains at least a date stamp and a hostname, and normally the program's name too, but that depends on how trusting the logging daemon is told to be.

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10.48. Sysvinit-2.86
The Sysvinit package contains programs for controlling the startup, running, and shutdown of the system.

10.48.1. Installation of Sysvinit
When run-levels are changed (for example, when halting the system), init sends termination signals to those processes that init itself started and that should not be running in the new run-level. While doing this, init outputs messages like “Sending processes the TERM signal” which seem to imply that it is sending these signals to all currently running processes. To avoid this misinterpretation, modify the source so that these messages read like “Sending processes started by init the TERM signal” instead: sed -i 's@Sending processes@& started by init@g' \ src/init.c Compile the package: make -C src clobber make -C src Install the package: make -C src install

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 halt Normally invokes shutdown with the -h option, except when already in run-level 0, then it tells the kernel to halt the system; it notes in the file /var/log/wtmp that the system is being brought down The first process to be started when the kernel has initialized the hardware which takes over the boot process and starts all the proceses it is instructed to Sends a signal to all processes, except the processes in its own session so it will not kill the shell running the script that called it Shows which users last logged in (and out), searching back through the /var/log/wtmp file; it also shows system boots, shutdowns, and run-level changes Shows the failed login attempts, as logged in /var/log/btmp Controls whether other users can send messages to the current user's terminal Tells you whether or not a directory is a mount point. Reports the PIDs of the given programs Tells the kernel to halt the system and switch off the computer (see halt) Tells the kernel to reboot the system (see halt) Reports the previous and the current run-level, as noted in the last run-level record in /var/run/utmp Brings the system down in a secure way, signaling all processes and notifying all logged-in users Allows root to log in; it is normally invoked by init when the system goes into single user mode Tells init which run-level to change to Displays the content of the given login file in a more user-friendly format Writes a message to all logged-in users

10.49.1. Installation of Tar
Prepare Tar for compilation: ./configure --prefix=/usr --bindir=/bin --libexecdir=/usr/sbin Compile the package: make To test the results, issue: make check. Install the package: make install

10.49.2. Contents of Tar
Installed programs: rmt and tar

Short Descriptions
rmt tar Remotely manipulates a magnetic tape drive through an interprocess communication connection Creates, extracts files from, and lists the contents of archives, also known as tarballs

10.50.1. Installation of Texinfo
Prepare Texinfo for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install The Info documentation system uses a plain text file to hold its list of menu entries. The file is located at /usr/share/info/dir. Unfortunately, due to occasional problems in the Makefiles of various packages, it can sometimes get out of sync with the info pages installed on the system. If the /usr/share/info/dir file ever needs to be recreated, the following optional commands will accomplish the task: cd /usr/share/info rm dir for f in * do install-info $f dir 2>/dev/null done

Short Descriptions
info infokey install-info makeinfo texi2dvi texi2pdf texindex Used to read info pages which are similar to man pages, but often go much deeper than just explaining all the command line options. For example, compare man bison and info bison. Compiles a source file containing Info customizations into a binary format Used to install info pages; it updates entries in the info index file Translates the given Texinfo source documents into info pages, plain text, or HTML Used to format the given Texinfo document into a device-independent file that can be printed Used to format the given Texinfo document into a Portable Document Format (PDF) file Used to sort Texinfo index files

EXTRAS="extras/ata_id extras/cdrom_id extras/collect extras/edd_id extras/firmware extras/floppy extras/path_id extras/rule_generator extras/scsi_id extras/usb_id extras/volume_id" This builds the helper applications that are used with udev. The helper programs assist in correct handling of devices. If you want to run the testsuite, you need to change a hardcoded reference to the test program: sed -i 's@/usr/bin/test@/bin/test@' test/udev-test.pl To test the results, issue: make test. Install the package:

DESTDIR=/ This prevents the Udev build process from killing any udevd processes that may be running on the system. Install documentation: install -v -m644 -D docs/writing_udev_rules/index.html \ /usr/share/doc/udev-124/index.html Create a directory for storing firmware that can be loaded by udev: install -dv /lib/firmware

Short Descriptions
udevadm This program combines udevinfo, udevtrigger, udevsettle, udevcontrol, udevmonitor, and udevtest into one command. 194

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 udevadm control udevd udevinfo Configures a number of options for the running udevd daemon, such as the log level. (Symlink to udevadm) A daemon that reorders hotplug events before submitting them to udev, thus avoiding various race conditions Allows users to query the udev database for information on any device currently present on the system; it also provides a way to query any device in the sysfs tree to help create udev rules. (Symlink to udevadm) Prints the event received from the kernel and the event which udev sends out after rule processing Watches the Udev event queue and exits if all current uevents have been handled. (Symlink to udevadm) Simulates a udev run for the given device, and prints out the name of the node the real udev would have created or the name of the renamed network interface Walks the sysfs tree for devices that need to be added to the system. Provides Udev with a unique string and additional information (uuid, label) for an ATA drive Print the capabilities of a CDROM or DVDROM drive. Creates all possible floppy devices based on the CMOS type Read the label from an s390 block device. Identify x86 disk drives from Enhanced Disk Drive calls. Script to load firmware for a device Provide the shortest possible unique hardware path to a device Retrieve or generate a unique SCSI identifier. Identify a USB block device. Probe filesystem type and read label and uuid. This library provides programs such as vol_id with a filesystems type, abel, and uuid from a device node or a image. Contains udev configuration files, device permissions, and rules for device naming Contains udev helper programs and static devices which get copied to /dev when booted.

10.52.1. FHS compliance notes
The FHS recommends using the /var/lib/hwclock directory instead of the usual /etc directory as the location for the adjtime file. To make the hwclock program FHS-compliant, run the following: sed -i 's@etc/adjtime@var/lib/hwclock/adjtime@g' \ hwclock/hwclock.c mkdir -pv /var/lib/hwclock

--enable-partx Enable partx stuff (need more description). --disable-wall Disables building the wall program, as the Sysvinit package installs its own version. --enable-write This option allows the write program to be installed. Compile the package: make This package does not come with a test suite. Install the package: make install Move the logger binary to /bin as it is needed by the CLFS-Bootscripts package: mv -v /usr/bin/logger /bin

Short Descriptions
addpart agetty blockdev cal cfdisk chkdupexe col colcrt colrm column ctrlaltdel cytune ddate delpart dmesg fdformat fdisk flock fsck.cramfs fsck.minix getopt hexdump hwclock ionice ipcrm ipcs isosize line logger look losetup mcookie mkfs mkfs.bfs Informs the kernel of a new partition Opens a tty port, prompts for a login name, and then invokes the login program Allows users to call block device ioctls from the command line Displays a simple calendar Manipulates the partition table of the given device Finds duplicate executables Filters out reverse line feeds Filters nroff output for terminals that lack some capabilities, such as overstriking and half-lines Filters out the given columns Formats a given file into multiple columns Sets the function of the Ctrl+Alt+Del key combination to a hard or a soft reset Tunes the parameters of the serial line drivers for Cyclades cards Gives the Discordian date or converts the given Gregorian date to a Discordian one Asks the kernel to remove a partition Dumps the kernel boot messages Low-level formats a floppy disk Manipulates the partition table of the given device Acquires a file lock and then executes a command with the lock held Performs a consistency check on the Cramfs file system on the given device Performs a consistency check on the Minix file system on the given device Parses options in the given command line Dumps the given file in hexadecimal or in another given format Reads or sets the system's hardware clock, also called the Real-Time Clock (RTC) or Basic Input-Output System (BIOS) clock Gives and sets program I/O scheduling class and priority Removes the given Inter-Process Communication (IPC) resource Provides IPC status information Reports the size of an iso9660 file system Copies a single line Enters the given message into the system log Displays lines that begin with the given string Sets up and controls loop devices Generates magic cookies (128-bit random hexadecimal numbers) for xauth Builds a file system on a device (usually a hard disk partition) Creates a Santa Cruz Operations (SCO) bfs file system 197

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 mkfs.cramfs mkfs.minix mkswap more mount namei partx pg pivot_root readprofile rename renice rev rtcwake script scriptreplay setarch setsid setterm sfdisk swapoff swapon tailf taskset tunelp ul umount whereis write Creates a cramfs file system Creates a Minix file system Initializes the given device or file to be used as a swap area A filter for paging through text one screen at a time Attaches the file system on the given device to a specified directory in the file-system tree Shows the symbolic links in the given pathnames Tells the kernel about the presence and numbering of on-disk partitions Displays a text file one screen full at a time Makes the given file system the new root file system of the current process Reads kernel profiling information Renames the given files, replacing a given string with another Alters the priority of running processes Reverses the lines of a given file Enters a system sleep state until a specified wakeup time Makes a typescript of a terminal session Plays back typescripts created by script Changes reported architecture in new program environment and sets personality flags Runs the given program in a new session Sets terminal attributes A disk partition table manipulator Disables devices and files for paging and swapping Enables devices and files for paging and swapping and lists the devices and files currently in use Tracks the growth of a log file. Displays the last 10 lines of a log file, then continues displaying any new entries in the log file as they are created Retrieves or sets a process's CPU affinity Tunes the parameters of the line printer A filter for translating underscores into escape sequences indicating underlining for the terminal in use Disconnects a file system from the system's file tree Reports the location of the binary, source, and man page for the given command Sends a message to the given user if that user has not disabled receipt of such messages

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10.53. Vim-7.1
The Vim package contains a powerful text editor.

Alternatives to Vim
If you prefer another editor—such as Emacs, Joe, or Nano—please refer to http://cblfs.cross-lfs.org/index. php/Category:Text_Editors for suggested installation instructions.

10.53.1. Installation of Vim
First, unpack both vim-7.1.tar.bz2 and (optionally) vim-7.1-lang.tar.gz archives into the same directory. The following patches merges all updates from the 7.1 Branch from the Vim developers: patch -Np1 -i ../vim-7.1-branch_update-2.patch Change the default location of the vimrc configuration file to /etc: echo '#define SYS_VIMRC_FILE "/etc/vimrc"' >> src/feature.h Prepare Vim for compilation: ./configure --prefix=/usr --enable-multibyte
The meaning of the configure options:

--enable-multibyte This optional but highly recommended switch enables support for editing files in multibyte character encodings. This is needed if using a locale with a multibyte character set. This switch is also helpful to be able to edit text files initially created in Linux distributions like Fedora Core that use UTF-8 as a default character set. Compile the package: make To test the results, issue: make test. However, this test suite outputs a lot of binary data to the screen, which can cause issues with the settings of the current terminal. This can be resolved by redirecting the output to a log file. Install the package: make install Many users are accustomed to using vi instead of vim. Some programs, such as vigr and vipw, also use vi. Create a symlink to permit execution of vim when users habitually enter vi and allow programs that use vi to work: ln -sv vim /usr/bin/vi By default, Vim's documentation is installed in /usr/share/vim. The following symlink allows the documentation to be accessed via /usr/share/doc/vim-7.1, making it consistent with the location of documentation for other packages: ln -sv ../vim/vim71/doc /usr/share/doc/vim-7.1 199

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 If an X Window System is going to be installed on the CLFS system, you may want to recompile Vim after installing X. Vim comes with a GUI version of the editor that requires X and some additional libraries to be installed. For more information, refer to the Vim documentation and the Vim installation page in the CBLFS book at http://cblfs. cross-lfs.org/index.php/Vim.

10.53.2. Configuring Vim
By default, vim runs in vi-incompatible mode. This may be new to users who have used other editors in the past. The “nocompatible” setting is included below to highlight the fact that a new behavior is being used. It also reminds those who would change to “compatible” mode that it should be the first setting in the configuration file. This is necessary because it changes other settings, and overrides must come after this setting. Create a default vim configuration file by running the following: cat > /etc/vimrc << "EOF" " Begin /etc/vimrc set nocompatible set backspace=2 syntax on if (&term == "iterm") || (&term == "putty") set background=dark endif " End /etc/vimrc EOF The set nocompatible makes vim behave in a more useful way (the default) than the vi-compatible manner. Remove the “no” to keep the old vi behavior. The set backspace=2 allows backspacing over line breaks, autoindents, and the start of insert. The syntax on enables vim's syntax highlighting. Finally, the if statement with the set background=dark corrects vim's guess about the background color of some terminal emulators. This gives the highlighting a better color scheme for use on the black background of these programs. Documentation for other available options can be obtained by running the following command: vim -c ':options'

Short Descriptions
efm_filter.pl efm_perl.pl ex less.sh mve.awk A filter for creating an error file that can be read by vim Reformats the error messages of the Perl interpreter for use with the “quickfix” mode of vim Starts vim in ex mode A script that starts vim with less.vim Processes vim errors 200

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 pltags.pl ref rview rvim shtags.pl tcltags view vi vim vim132 vim2html.pl vimdiff vimm vimspell.sh vimtutor xxd Creates a tags file for Perl code for use by vim Checks the spelling of arguments Is a restricted version of view; no shell commands can be started and view cannot be suspended Is a restricted version of vim; no shell commands can be started and vim cannot be suspended Generates a tags file for Perl scripts Generates a tags file for TCL code Starts vim in read-only mode Link to vim Is the editor Starts vim with the terminal in 132-column mode Converts Vim documentation to HypterText Markup Language (HTML) Edits two or three versions of a file with vim and show differences Enables the DEC locator input model on a remote terminal Spell checks a file and generates the syntax statements necessary to highlight in vim. This script requires the old Unix spell command, which is provided neither in CLFS nor in CBLFS Teaches the basic keys and commands of vim Creates a hex dump of the given file; it can also do the reverse, so it can be used for binary patching

10.54.1. Installation of GRUB
GRUB has an issue where it sometimes doesn't detect the disk geometry correctly when used with Linux 2.6, resulting in the error message Error 24: Attempt to access block outside partition. The following patch contains a fix for this issue as well as various fixes for raid controllers and support for the new Intel Mac: patch -Np1 -i ../grub-0.97-fixes-1.patch By default, GRUB doesn't support ext2 filesystems with 256-byte inodes. Fix this by applying the following patch: patch -Np1 -i ../grub-0.97-256byte_inode-1.patch This package is known to have issues when its default optimization flags (including the -march and -mcpu options) are changed. If any environment variables that override default optimizations have been defined, such as CFLAGS and CXXFLAGS, unset them when building GRUB. Prepare GRUB for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check. Install the package: make install mkdir -pv /boot/grub cp -v /usr/lib/grub/*/stage{1,2} /boot/grub The directory in /usr/lib/grub (its name depends on your arch) contains a number of *stage1_5 files, different ones for different file systems. Review the files available and copy the appropriate ones to the /boot/grub directory. Most users will copy the e2fs_stage1_5 and/or reiserfs_stage1_5 files.

Short Descriptions
grub grub-install grub-md5-crypt grub-set-default grub-terminfo The Grand Unified Bootloader's command shell Installs GRUB on the given device Encrypts a password in MD5 format Sets the default boot entry for GRUB Generates a terminfo command from a terminfo name; it can be employed if an unknown terminal is being used 202

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 mbchk Checks the format of a multi-boot kernel

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10.55. About Debugging Symbols
Most programs and libraries are, by default, compiled with debugging symbols included (with gcc's -g option). This means that when debugging a program or library that was compiled with debugging information included, the debugger can provide not only memory addresses, but also the names of the routines and variables. However, the inclusion of these debugging symbols enlarges a program or library significantly. The following is an example of the amount of space these symbols occupy: • a bash binary with debugging symbols: 1200 KB • a bash binary without debugging symbols: 480 KB • Glibc and GCC files (/lib and /usr/lib) with debugging symbols: 87 MB • Glibc and GCC files without debugging symbols: 16 MB Sizes may vary depending on which compiler and C library were used, but when comparing programs with and without debugging symbols, the difference will usually be a factor between two and five. Because most users will never use a debugger on their system software, a lot of disk space can be regained by removing these symbols. The next section shows how to strip all debugging symbols from the programs and libraries.

10.56. Stripping
If the intended user is not a programmer and does not plan to do any debugging on the system software, the system size can be decreased by about 200 MB by removing the debugging symbols from binaries and libraries. This causes no inconvenience other than not being able to debug the software fully anymore. Most people who use the command mentioned below do not experience any difficulties. However, it is easy to make a typo and render the new system unusable, so before running the strip command, it is a good idea to make a backup of the current situation. Before performing the stripping, take special care to ensure that none of the binaries that are about to be stripped are running. If unsure whether the user entered chroot with the command given in If You Are Going to Chroot first exit from chroot: logout Then reenter it with: chroot ${CLFS} /tools/bin/env -i \ HOME=/root TERM=${TERM} PS1='\u:\w\$ ' \ PATH=/bin:/usr/bin:/sbin:/usr/sbin \ /tools/bin/bash --login Now the binaries and libraries can be safely stripped: /tools/bin/find /{,usr/}{bin,lib,sbin} -type f \ -exec /tools/bin/strip --strip-debug '{}' ';' A large number of files will be reported as having their file format not recognized. These warnings can be safely ignored. These warnings indicate that those files are scripts instead of binaries. If disk space is very tight, the --strip-all option can be used on the binaries in /{,usr/}{bin,sbin} to gain several more megabytes. Do not use this option on libraries—they will be destroyed. 204

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Chapter 11. Setting Up System Bootscripts
11.1. Introduction
This chapter details how to install and configure the CLFS-Bootscripts package. Most of these scripts will work without modification, but a few require additional configuration files because they deal with hardware-dependent information. System-V style init scripts are employed in this book because they are widely used. For additional options, a hint detailing the BSD style init setup is available at http://hints.cross-lfs.org/bsd-init.txt. Searching the LFS mailing lists for “depinit” will also offer additional choices. If using an alternative style of init scripts, skip this chapter and move on to Making the CLFS System Bootable.

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11.2. CLFS-Bootscripts-1.1.0
The CLFS-Bootscripts package contains a set of scripts to start/stop the CLFS system at bootup/shutdown.

11.2.1. Installation of CLFS-Bootscripts
Install the package: make install-bootscripts

Short Descriptions
checkfs cleanfs Checks the integrity of the file systems before they are mounted (with the exception of journal and network based file systems) Removes files that should not be preserved between reboots, such as those in /var/run/ and /var/lock/; it re-creates /var/run/utmp and removes the possibly present /etc/nologin, /fastboot, and /forcefsck files Loads the correct keymap table for the desired keyboard layout; it also sets the screen font Contains common functions, such as error and status checking, that are used by several bootscripts Halts the system Assists the network script with stopping network devices Assists the network script with starting network devices Sets up the system's hostname and local loopback device Mounts all file systems, except ones that are marked noauto or are network based Mounts virtual kernel file systems, such as proc Sets up network interfaces, such as network cards, and sets up the default gateway (where applicable) The master run-level control script; it is responsible for running all the other bootscripts one-by-one, in a sequence determined by the name of the symbolic links being processed Reboots the system Makes sure every process is terminated before the system reboots or halts Resets the kernel clock to local time in case the hardware clock is not set to UTC time Provides the functionality needed to assign a static Internet Protocol (IP) address to a network interface Enables and disables swap files and partitions Starts and stops the system and kernel log daemons A template to create custom bootscripts for other daemons

11.3. How Do These Bootscripts Work?
Linux uses a special booting facility named SysVinit that is based on a concept of run-levels. It can be quite different from one system to another, so it cannot be assumed that because things worked in one particular Linux distribution, they should work the same in CLFS too. CLFS has its own way of doing things, but it respects generally accepted standards. SysVinit (which will be referred to as “init” from now on) works using a run-levels scheme. There are seven (numbered 0 to 6) run-levels (actually, there are more run-levels, but they are for special cases and are generally not used. See init(8) for more details), and each one of those corresponds to the actions the computer is supposed to perform when it starts up. The default run-level is 3. Here are the descriptions of the different run-levels as they are implemented: 0: halt the computer 1: single-user mode 2: multi-user mode without networking 3: multi-user mode with networking 4: reserved for customization, otherwise does the same as 3 5: same as 4, it is usually used for GUI login (like X's xdm or KDE's kdm) 6: reboot the computer The command used to change run-levels is init [runlevel], where [runlevel] is the target run-level. For example, to reboot the computer, a user could issue the init 6 command, which is an alias for the reboot command. Likewise, init 0 is an alias for the halt command. There are a number of directories under /etc/rc.d that look like rc?.d (where ? is the number of the run-level) and rcsysinit.d, all containing a number of symbolic links. Some begin with a K, the others begin with an S, and all of them have two numbers following the initial letter. The K means to stop (kill) a service and the S means to start a service. The numbers determine the order in which the scripts are run, from 00 to 99—the lower the number the earlier it gets executed. When init switches to another run-level, the appropriate services are either started or stopped, depending on the runlevel chosen. The real scripts are in /etc/rc.d/init.d. They do the actual work, and the symlinks all point to them. Killing links and starting links point to the same script in /etc/rc.d/init.d. This is because the scripts can be called with different parameters like start, stop, restart, reload, and status. When a K link is encountered, the appropriate script is run with the stop argument. When an S link is encountered, the appropriate script is run with the start argument. There is one exception to this explanation. Links that start with an S in the rc0.d and rc6.d directories will not cause anything to be started. They will be called with the parameter stop to stop something. The logic behind this is that when a user is going to reboot or halt the system, nothing needs to be started. The system only needs to be stopped. These are descriptions of what the arguments make the scripts do: start The service is started. stop The service is stopped. restart The service is stopped and then started again. 207

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 reload The configuration of the service is updated. This is used after the configuration file of a service was modified, when the service does not need to be restarted. status Tells if the service is running and with which PIDs. Feel free to modify the way the boot process works (after all, it is your own CLFS system). The files given here are an example of how it can be done.

11.4. Device and Module Handling on a CLFS System
In Installing Basic System Software, we installed the Udev package. Before we go into the details regarding how this works, a brief history of previous methods of handling devices is in order. Linux systems in general traditionally use a static device creation method, whereby a great many device nodes are created under /dev (sometimes literally thousands of nodes), regardless of whether the corresponding hardware devices actually exist. This is typically done via a MAKEDEV script, which contains a number of calls to the mknod program with the relevant major and minor device numbers for every possible device that might exist in the world. Using the Udev method, only those devices which are detected by the kernel get device nodes created for them. Because these device nodes will be created each time the system boots, they will be stored on a tmpfs file system (a virtual file system that resides entirely in system memory). Device nodes do not require much space, so the memory that is used is negligible.

11.4.1. History
In February 2000, a new filesystem called devfs was merged into the 2.3.46 kernel and was made available during the 2.4 series of stable kernels. Although it was present in the kernel source itself, this method of creating devices dynamically never received overwhelming support from the core kernel developers. The main problem with the approach adopted by devfs was the way it handled device detection, creation, and naming. The latter issue, that of device node naming, was perhaps the most critical. It is generally accepted that if device names are allowed to be configurable, then the device naming policy should be up to a system administrator, not imposed on them by any particular developer(s). The devfs file system also suffers from race conditions that are inherent in its design and cannot be fixed without a substantial revision to the kernel. It has also been marked as deprecated due to a lack of recent maintenance. With the development of the unstable 2.5 kernel tree, later released as the 2.6 series of stable kernels, a new virtual filesystem called sysfs came to be. The job of sysfs is to export a view of the system's hardware configuration to userspace processes. With this userspace-visible representation, the possibility of seeing a userspace replacement for devfs became much more realistic.

11.4.2. Udev Implementation
11.4.2.1. Sysfs
The sysfs filesystem was mentioned briefly above. One may wonder how sysfs knows about the devices present on a system and what device numbers should be used for them. Drivers that have been compiled into the kernel directly register their objects with sysfs as they are detected by the kernel. For drivers compiled as modules, this registration will happen when the module is loaded. Once the sysfs filesystem is mounted (on /sys), data which the built-in drivers registered with sysfs are available to userspace processes and to udevd for device node creation. 208

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11.4.2.2. Udev Bootscript
The S10udev initscript takes care of creating device nodes when Linux is booted. The script unsets the uevent handler from the default of /sbin/hotplug. This is done because the kernel no longer needs to call out to an external binary. Instead udevd will listen on a netlink socket for uevents that the kernel raises. Next, the bootscript copies any static device nodes that exist in /lib/udev/devices to /dev. This is necessary because some devices, directories, and symlinks are needed before the dynamic device handling processes are available during the early stages of booting a system. Creating static device nodes in /lib/udev/devices also provides an easy workaround for devices that are not supported by the dynamic device handling infrastructure. The bootscript then starts the Udev daemon, udevd, which will act on any uevents it receives. Finally, the bootscript forces the kernel to replay uevents for any devices that have already been registered and then waits for udevd to handle them.

11.4.2.3. Device Node Creation
To obtain the right major and minor number for a device, Udev relies on the information provided by sysfs in /sys. For example, /sys/class/tty/vcs/dev contains the string “7:0”. This string is used by udevd to create a device node with major number 7 and minor 0. The names and permissions of the nodes created under the /dev directory are determined by rules specified in the files within the /etc/udev/rules.d/ directory. These are numbered in a similar fashion to the CLFS-Bootscripts package. If udevd can't find a rule for the device it is creating, it will default permissions to 660 and ownership to root:root. Documentation on the syntax of the Udev rules configuration files are available in /usr/share/doc/udev-124/index.html

11.4.2.4. Module Loading
Device drivers compiled as modules may have aliases built into them. Aliases are visible in the output of the modinfo program and are usually related to the bus-specific identifiers of devices supported by a module. For example, the snd-fm801 driver supports PCI devices with vendor ID 0x1319 and device ID 0x0801, and has an alias of “pci:v00001319d00000801sv*sd*bc04sc01i*”. For most devices, the bus driver exports the alias of the driver that would handle the device via sysfs. E.g., the /sys/bus/pci/devices/0000:00:0d.0/modalias file might contain the string “pci:v00001319d00000801sv00001319sd00001319bc04sc01i00”. The rules that CLFS installs will cause udevd to call out to /sbin/modprobe with the contents of the MODALIAS uevent environment variable (that should be the same as the contents of the modalias file in sysfs), thus loading all modules whose aliases match this string after wildcard expansion. In this example, this means that, in addition to snd-fm801, the obsolete (and unwanted) forte driver will be loaded if it is available. See below for ways in which the loading of unwanted drivers can be prevented. The kernel itself is also able to load modules for network protocols, filesystems and NLS support on demand.

11.4.2.5. Handling Hotpluggable/Dynamic Devices
When you plug in a device, such as a Universal Serial Bus (USB) MP3 player, the kernel recognizes that the device is now connected and generates a uevent. This uevent is then handled by udevd as described above.

11.4.3. Problems with Loading Modules and Creating Devices
There are a few possible problems when it comes to automatically creating device nodes.

11.4.3.1. A kernel module is not loaded automatically
Udev will only load a module if it has a bus-specific alias and the bus driver properly exports the necessary aliases to sysfs. In other cases, one should arrange module loading by other means. With Linux-2.6.24.7, Udev is known to load properly-written drivers for INPUT, IDE, PCI, USB, SCSI, SERIO and FireWire devices. 209

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 To determine if the device driver you require has the necessary support for Udev, run modinfo with the module name as the argument. Now try locating the device directory under /sys/bus and check whether there is a modalias file there. If the modalias file exists in sysfs, the driver supports the device and can talk to it directly, but doesn't have the alias, it is a bug in the driver. Load the driver without the help from Udev and expect the issue to be fixed later. If there is no modalias file in the relevant directory under /sys/bus, this means that the kernel developers have not yet added modalias support to this bus type. With Linux-2.6.24.7, this is the case with ISA busses. Expect this issue to be fixed in later kernel versions. Udev is not intended to load “wrapper” drivers such as snd-pcm-oss and non-hardware drivers such as loop at all.

11.4.3.2. A kernel module is not loaded automatically, and Udev is not intended to load it
If the “wrapper” module only enhances the functionality provided by some other module (e.g., snd-pcm-oss enhances the functionality of snd-pcm by making the sound cards available to OSS applications), configure modprobe to load the wrapper after Udev loads the wrapped module. To do this, add an “install” line in /etc/modprobe.conf. For example: install snd-pcm /sbin/modprobe -i snd-pcm ; \ /sbin/modprobe snd-pcm-oss ; true If the module in question is not a wrapper and is useful by itself, configure the S05modules bootscript to load this module on system boot. To do this, add the module name to the /etc/sysconfig/modules file on a separate line. This works for wrapper modules too, but is suboptimal in that case.

11.4.3.3. Udev loads some unwanted module
Either don't build the module, or blacklist it in /etc/modprobe.conf file as done with the forte module in the example below: blacklist forte Blacklisted modules can still be loaded manually with the explicit modprobe command.

11.4.3.4. Udev creates a device incorrectly, or makes a wrong symlink
This usually happens if a rule unexpectedly matches a device. For example, a poorly-writen rule can match both a SCSI disk (as desired) and the corresponding SCSI generic device (incorrectly) by vendor. Find the offending rule and make it more specific.

11.4.3.5. Udev rule works unreliably
This may be another manifestation of the previous problem. If not, and your rule uses sysfs attributes, it may be a kernel timing issue, to be fixed in later kernels. For now, you can work around it by creating a rule that waits for the used sysfs attribute and appending it to the /etc/udev/rules.d/10-wait_for_sysfs.rules file. Please notify the CLFS Development list if you do so and it helps.

11.4.3.6. Udev does not create a device
Further text assumes that the driver is built statically into the kernel or already loaded as a module, and that you have already checked that Udev doesn't create a misnamed device. 210

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Udev has no information needed to create a device node if a kernel driver does not export its data to sysfs. This is most common with third party drivers from outside the kernel tree. Create a static device node in /lib/udev/devices with the appropriate major/minor numbers (see the file devices.txt inside the kernel documentation or the documentation provided by the third party driver vendor). The static device node will be copied to /dev by the S10udev bootscript.

11.4.3.7. Device naming order changes randomly after rebooting
This is due to the fact that Udev, by design, handles uevents and loads modules in parallel, and thus in an unpredictable order. This will never be “fixed”. You should not rely upon the kernel device names being stable. Instead, create your own rules that make symlinks with stable names based on some stable attributes of the device, such as a serial number or the output of various *_id utilities installed by Udev. See Section 11.12, “Creating custom symlinks to devices” and Section 11.13, “Configuring the network Script” for examples.

11.5. Configuring the setclock Script
The setclock script reads the time from the hardware clock, also known as the BIOS or the Complementary Metal Oxide Semiconductor (CMOS) clock. If the hardware clock is set to UTC, this script will convert the hardware clock's time to the local time using the /etc/localtime file (which tells the hwclock program which timezone the user is in). There is no way to detect whether or not the hardware clock is set to UTC, so this needs to be configured manually. If you cannot remember whether or not the hardware clock is set to UTC, find out by running the hwclock --localtime --show command. This will display what the current time is according to the hardware clock. If this time matches whatever your watch says, then the hardware clock is set to local time. If the output from hwclock is not local time, chances are it is set to UTC time. Verify this by adding or subtracting the proper amount of hours for the timezone to the time shown by hwclock. For example, if you are currently in the MST timezone, which is also known as GMT -0700, add seven hours to the local time. Change the value of the UTC variable below to a value of 0 (zero) if the hardware clock is not set to UTC time. Create a new file /etc/sysconfig/clock by running the following: cat > /etc/sysconfig/clock << "EOF" # Begin /etc/sysconfig/clock UTC=1 # End /etc/sysconfig/clock EOF 211

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 A good hint explaining how to deal with time on CLFS is available at http://hints.cross-lfs.org/time.txt. It explains issues such as time zones, UTC, and the TZ environment variable.

11.6. Configuring the Linux Console
This section discusses how to configure the console bootscript that sets up the keyboard map and the console font. If non-ASCII characters (e.g., the British pound sign and Euro character) will not be used and the keyboard is a U.S. one, skip this section. Without the configuration file, the console bootscript will do nothing. The console script reads the /etc/sysconfig/console file for configuration information. Decide which keymap and screen font will be used. Various language-specific HOWTO's can also help with this (see http://www. tldp.org/HOWTO/HOWTO-INDEX/other-lang.html. A pre-made /etc/sysconfig/console file with known settings for several countries was installed with the CLFS-Bootscripts package, so the relevant section can be uncommented if the country is supported. If still in doubt, look in the /lib/kbd directory for valid keymaps and screen fonts. Read loadkeys(1) and setfont(8) to determine the correct arguments for these programs. Once decided, create the configuration file with the following command: cat >/etc/sysconfig/console <<"EOF" KEYMAP="[arguments for loadkeys]" FONT="[arguments for setfont]" EOF For example, for Spanish users who also want to use the Euro character (accessible by pressing AltGr+E), the following settings are correct: cat >/etc/sysconfig/console <<"EOF" KEYMAP="es euro2" FONT="lat9-16 -u iso01" EOF

Note
The FONT line above is correct only for the ISO 8859-15 character set. If using ISO 8859-1 and, therefore, a pound sign instead of Euro, the correct FONT line would be: FONT="lat1-16" If the KEYMAP or FONT variable is not set, the console initscript will not run the corresponding program. In some keymaps, the Backspace and Delete keys send characters different from ones in the default keymap built into the kernel. This confuses some applications. For example, Emacs displays its help (instead of erasing the character before the cursor) when Backspace is pressed. To check if the keymap in use is affected (this works only for i386 keymaps): zgrep '\W14\W' [/path/to/your/keymap]

Tell the console script to load this snippet after the main keymap: cat >>/etc/sysconfig/console <<"EOF" KEYMAP_CORRECTIONS="/etc/kbd/bs-sends-del" EOF

11.7. Configuring the sysklogd script
The sysklogd script invokes the syslogd program with the -m 0 option. This option turns off the periodic timestamp mark that syslogd writes to the log files every 20 minutes by default. If you want to turn on this periodic timestamp mark, edit the sysklogd script and make the changes accordingly. See man syslogd for more information.

11.8. Creating the /etc/inputrc File
The /etc/inputrc file deals with mapping the keyboard for specific situations. This file is the start-up file used by Readline — the input-related library — used by Bash and most other shells. Most people do not need user-specific keyboard mappings so the command below creates a global /etc/inputrc used by everyone who logs in. If you later decide you need to override the defaults on a per-user basis, you can create a .inputrc file in the user's home directory with the modified mappings. For more information on how to edit the inputrc file, see info bash under the Readline Init File section. info readline is also a good source of information. Below is a generic global inputrc along with comments to explain what the various options do. Note that comments cannot be on the same line as commands. Create the file using the following command: cat > /etc/inputrc << "EOF" # Begin /etc/inputrc # Modified by Chris Lynn <roryo@roryo.dynup.net> # Allow the command prompt to wrap to the next line set horizontal-scroll-mode Off # Enable 8bit input set meta-flag On set input-meta On

11.9. The Bash Shell Startup Files
The shell program /bin/bash (hereafter referred to as “the shell”) uses a collection of startup files to help create an environment to run in. Each file has a specific use and may affect login and interactive environments differently. The files in the /etc directory provide global settings. If an equivalent file exists in the home directory, it may override the global settings. An interactive login shell is started after a successful login, using /bin/login, by reading the /etc/passwd file. An interactive non-login shell is started at the command-line (e.g., [prompt]$/bin/bash). A non-interactive shell is usually present when a shell script is running. It is non-interactive because it is processing a script and not waiting for user input between commands. For more information, see info bash under the Bash Startup Files and Interactive Shells section. 214

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 The files /etc/profile and ~/.bash_profile are read when the shell is invoked as an interactive login shell. The base /etc/profile below sets some environment variables necessary for native language support. Setting them properly results in: • The output of programs translated into the native language • Correct classification of characters into letters, digits and other classes. This is necessary for bash to properly accept non-ASCII characters in command lines in non-English locales • The correct alphabetical sorting order for the country • Appropriate default paper size • Correct formatting of monetary, time, and date values This script also sets the INPUTRC environment variable that makes Bash and Readline use the /etc/inputrc file created earlier. Replace [ll] below with the two-letter code for the desired language (e.g., “en”) and [CC] with the two-letter code for the appropriate country (e.g., “GB”). [charmap] should be replaced with the canonical charmap for your chosen locale. The list of all locales supported by Glibc can be obtained by running the following command: locale -a Locales can have a number of synonyms, e.g. “ISO-8859-1” is also referred to as “iso8859-1” and “iso88591”. Some applications cannot handle the various synonyms correctly, so it is safest to choose the canonical name for a particular locale. To determine the canonical name, run the following command, where [locale name] is the output given by locale -a for your preferred locale (“en_GB.iso88591” in our example). LC_ALL=[locale name] locale charmap For the “en_GB.iso88591” locale, the above command will print: ISO-8859-1 This results in a final locale setting of “en_GB.ISO-8859-1”. It is important that the locale found using the heuristic above is tested prior to it being added to the Bash startup files: LC_ALL=[locale LC_ALL=[locale LC_ALL=[locale LC_ALL=[locale LC_ALL=[locale name] name] name] name] name] locale locale locale locale locale country language charmap int_curr_symbol int_prefix

The above commands should print the language name, the character encoding used by the locale, the local currency, and the prefix to dial before the telephone number in order to get into the country. If any of the commands above fail with a message similar to the one shown below, this means that your locale was either not installed in Chapter 10 or is not supported by the default installation of Glibc. locale: Cannot set LC_* to default locale: No such file or directory If this happens, you should either install the desired locale using the localedef command, or consider choosing a different locale. Further instructions assume that there are no such error messages from Glibc. 215

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Some packages beyond CLFS may also lack support for your chosen locale. One example is the X library (part of the X Window System), which outputs the following error message: Warning: locale not supported by Xlib, locale set to C Sometimes it is possible to fix this by removing the charmap part of the locale specification, as long as that does not change the character map that Glibc associates with the locale (this can be checked by running the locale charmap command in both locales). For example, one would have to change "de_DE.ISO-8859-15@euro" to "de_DE@euro" in order to get this locale recognized by Xlib. Other packages can also function incorrectly (but may not necessarily display any error messages) if the locale name does not meet their expectations. In those cases, investigating how other Linux distributions support your locale might provide some useful information. Once the proper locale settings have been determined, create the /etc/profile file: cat > /etc/profile << "EOF" # Begin /etc/profile export LANG=[ll]_[CC].[charmap] export INPUTRC=/etc/inputrc # End /etc/profile EOF

Note
The “C” (default) and “en_US” (the recommended one for United States English users) locales are different. Setting the keyboard layout, screen font, and locale-related environment variables are the only internationalization steps needed to support locales that use ordinary single-byte encodings and left-to-right writing direction. More complex cases (including UTF-8 based locales) require additional steps and additional patches because many applications tend to not work properly under such conditions. These steps and patches are not included in the CLFS book and such locales are not yet supported by CLFS.

11.10. Configuring the localnet Script
Part of the job of the localnet script is setting the system's hostname. This needs to be configured in the /etc/sysconfig/network file. Create the /etc/sysconfig/network file and enter a hostname by running: echo "HOSTNAME=[clfs]" > /etc/sysconfig/network [clfs] needs to be replaced with the name given to the computer. Do not enter the Fully Qualified Domain Name (FQDN) here. That information will be put in the /etc/hosts file in the next section.

11.11. Customizing the /etc/hosts File
If a network card is to be configured, decide on the IP address, FQDN, and possible aliases for use in the /etc/hosts file. The syntax is: <IP address> myhost.example.org aliases 216

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Unless the computer is to be visible to the Internet (i.e., there is a registered domain and a valid block of assigned IP addresses—most users do not have this), make sure that the IP address is in the private network IP address range. Valid ranges are: Class A B C Networks 10.0.0.0 172.16.0.0 through 172.31.0.255 192.168.0.0 through 192.168.255.255

A valid IP address could be 192.168.1.1. A valid FQDN for this IP could be www.linuxfromscratch.org (not recommended because this is a valid registered domain address and could cause domain name server issues). Even if not using a network card, an FQDN is still required. This is necessary for certain programs to operate correctly. Create the /etc/hosts file by running: cat > /etc/hosts << "EOF" # Begin /etc/hosts (network card version) 127.0.0.1 localhost [192.168.1.1] [<HOSTNAME>.example.org] [HOSTNAME] # End /etc/hosts (network card version) EOF The [192.168.1.1] and [<HOSTNAME>.example.org] values need to be changed for specific users or requirements (if assigned an IP address by a network/system administrator and the machine will be connected to an existing network). If a network card is not going to be configured, create the /etc/hosts file by running: cat > /etc/hosts << "EOF" # Begin /etc/hosts (no network card version) 127.0.0.1 [<HOSTNAME>.example.org] [HOSTNAME] localhost # End /etc/hosts (no network card version) EOF

11.12. Creating custom symlinks to devices
11.12.1. CD-ROM symlinks
Some software that you may want to install later (e.g., various media players) expect the /dev/cdrom and /dev/dvd symlinks to exist. Also, it may be convenient to put references to those symlinks into /etc/fstab. For each of your CD-ROM devices, find the corresponding directory under /sys (e.g., this can be /sys/block/hdd) and run a command similar to the following: udevadm test /sys/block/hdd Look at the lines containing the output of various *_id programs. 217

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 There are two approaches to creating symlinks. The first one is to use the model name and the serial number, the second one is based on the location of the device on the bus. If you are going to use the first approach, create a file similar to the following: cat >/etc/udev/rules.d/82-cdrom.rules << EOF # Custom CD-ROM symlinks SUBSYSTEM=="block", ENV{ID_MODEL}=="SAMSUNG_CD-ROM_SC-148F", \ ENV{ID_REVISION}=="PS05", SYMLINK+="cdrom" SUBSYSTEM=="block", ENV{ID_MODEL}=="PHILIPS_CDD5301", \ ENV{ID_SERIAL}=="5VO1306DM00190", SYMLINK+="cdrom1 dvd" EOF

Note
Although the examples in this book work properly, be aware that Udev does not recognize the backslash for line continuation. If modifying Udev rules with an editor, be sure to leave each rule on one physical line. This way, the symlinks will stay correct even if you move the drives to different positions on the IDE bus, but the /dev/cdrom symlink won't be created if you replace the old SAMSUNG CD-ROM with a new drive. The SUBSYSTEM=="block" key is needed in order to avoid matching SCSI generic devices. Without it, in the case with SCSI CD-ROMs, the symlinks will sometimes point to the correct /dev/srX devices, and sometimes to /dev/sgX, which is wrong. The second approach yields: cat >/etc/udev/rules.d/82-cdrom.rules << EOF # Custom CD-ROM symlinks SUBSYSTEM=="block", ENV{ID_TYPE}=="cd", \ ENV{ID_PATH}=="pci-0000:00:07.1-ide-0:1", SYMLINK+="cdrom" SUBSYSTEM=="block", ENV{ID_TYPE}=="cd", \ ENV{ID_PATH}=="pci-0000:00:07.1-ide-1:1", SYMLINK+="cdrom1 dvd" EOF This way, the symlinks will stay correct even if you replace drives with different models, but place them to the old positions on the IDE bus. The ENV{ID_TYPE}=="cd" key makes sure that the symlink disappears if you put something other than a CD-ROM in that position on the bus. Of course, it is possible to mix the two approaches.

11.12.2. Dealing with duplicate devices
As explained in Section 11.4, “Device and Module Handling on a CLFS System”, the order in which devices with the same function appear in /dev is essentially random. E.g., if you have a USB web camera and a TV tuner, sometimes /dev/video0 refers to the camera and /dev/video1 refers to the tuner, and sometimes after a reboot the order changes to the opposite one. For all classes of hardware except sound cards and network cards, this is fixable by creating udev rules for custom persistent symlinks. The case of network cards is covered separately in Section 11.13, “Configuring the network Script”, and sound card configuration can be found in CBLFS. 218

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 For each of your devices that is likely to have this problem (even if the problem doesn't exist in your current Linux distribution), find the corresponding directory under /sys/class or /sys/block. For video devices, this may be /sys/class/video4linux/videoX. Figure out the attributes that identify the device uniquely (usually, vendor and product IDs and/or serial numbers work): udevadm info -a -p /sys/class/video4linux/video0 Then write rules that create the symlinks, e.g.: cat >/etc/udev/rules.d/83-duplicate_devs.rules << EOF # Persistent symlinks for webcam and tuner KERNEL=="video*", SYSFS{idProduct}=="1910", SYSFS{idVendor}=="0d81", \ SYMLINK+="webcam" KERNEL=="video*", SYSFS{device}=="0x036f", SYSFS{vendor}=="0x109e", \ SYMLINK+="tvtuner" EOF The result is that /dev/video0 and /dev/video1 devices still refer randomly to the tuner and the web camera (and thus should never be used directly), but there are symlinks /dev/tvtuner and /dev/webcam that always point to the correct device. More information on writing Udev rules can be found in /usr/share/doc/udev-124/index.html.

11.13. Configuring the network Script
This section only applies if a network card is to be configured. If a network card will not be used, there is likely no need to create any configuration files relating to network cards. If that is the case, remove the network symlinks from all run-level directories (/etc/rc.d/rc*.d).

11.13.1. Creating Network Interface Configuration Files
Which interfaces are brought up and down by the network script depends on the files and directories in the /etc/sysconfig/network-devices hierarchy. This directory should contain a sub-directory for each interface to be configured, such as ifconfig.xyz, where “xyz” is a network interface name. Inside this directory would be files defining the attributes to this interface, such as its IP address(es), subnet masks, and so forth. The following command creates a sample ipv4 file for the eth0 device: cd /etc/sysconfig/network-devices && mkdir -v ifconfig.eth0 && cat > ifconfig.eth0/ipv4 << "EOF" ONBOOT=yes SERVICE=ipv4-static IP=192.168.1.1 GATEWAY=192.168.1.2 PREFIX=24 BROADCAST=192.168.1.255 EOF 219

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 The values of these variables must be changed in every file to match the proper setup. If the ONBOOT variable is set to “yes” the network script will bring up the Network Interface Card (NIC) during booting of the system. If set to anything but “yes” the NIC will be ignored by the network script and not be brought up. The SERVICE variable defines the method used for obtaining the IP address. The CLFS-Bootscripts package has a modular IP assignment format, and creating additional files in the /etc/sysconfig/network-devices/services directory allows other IP assignment methods. This is commonly used for Dynamic Host Configuration Protocol (DHCP), which is addressed in the BLFS book. The GATEWAY variable should contain the default gateway IP address, if one is present. If not, then comment out the variable entirely. The PREFIX variable needs to contain the number of bits used in the subnet. Each octet in an IP address is 8 bits. If the subnet's netmask is 255.255.255.0, then it is using the first three octets (24 bits) to specify the network number. If the netmask is 255.255.255.240, it would be using the first 28 bits. Prefixes longer than 24 bits are commonly used by DSL and cable-based Internet Service Providers (ISPs). In this example (PREFIX=24), the netmask is 255.255.255.0. Adjust the PREFIX variable according to your specific subnet.

11.13.2. Creating the /etc/resolv.conf File
If the system is going to be connected to the Internet, it will need some means of Domain Name Service (DNS) name resolution to resolve Internet domain names to IP addresses, and vice versa. This is best achieved by placing the IP address of the DNS server, available from the ISP or network administrator, into /etc/resolv.conf. Create the file by running the following: cat > /etc/resolv.conf << "EOF" # Begin /etc/resolv.conf domain [Your Domain Name] nameserver [IP address of your primary nameserver] nameserver [IP address of your secondary nameserver] # End /etc/resolv.conf EOF Replace [IP address of the nameserver] with the IP address of the DNS most appropriate for the setup. There will often be more than one entry (requirements demand secondary servers for fallback capability). If you only need or want one DNS server, remove the second nameserver line from the file. The IP address may also be a router on the local network.

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Chapter 12. Making the CLFS System Bootable
12.1. Introduction
It is time to make the CLFS system bootable. This chapter discusses creating an fstab file, building a kernel for the new CLFS system, and installing the boot loader so that the CLFS system can be selected for booting at startup.

12.2. Creating the /etc/fstab File
The /etc/fstab file is used by some programs to determine where file systems are to be mounted by default, in which order, and which must be checked (for integrity errors) prior to mounting. Create a new file systems table like this: cat > /etc/fstab << "EOF" # Begin /etc/fstab # file system # mount-point type options dump fsck order 1 0 0 0 0 0

Replace [xxx], [yyy], and [fff] with the values appropriate for the system, for example, hda2, hda5, and ext2. For details on the six fields in this file, see man 5 fstab. The /dev/shm mount point for tmpfs is included to allow enabling POSIX-shared memory. The kernel must have the required support built into it for this to work (more about this is in the next section). Please note that very little software currently uses POSIX-shared memory. Therefore, consider the /dev/shm mount point optional. For more information, see Documentation/filesystems/tmpfs.txt in the kernel source tree.

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12.3. Linux-2.6.24.7
The Linux package contains the Linux kernel.

12.3.1. Installation of the kernel
A number of vulnerabilities have come to light after the stable kernel team stopped supporting 2.6.24. The following patch addresses them: patch -Np1 -i ../linux-2.6.24.7-security_fixes-1.patch Building the kernel involves a few steps—configuration, compilation, and installation. Read the README file in the kernel source tree for alternative methods to the way this book configures the kernel. Prepare for compilation by running the following command: make mrproper This ensures that the kernel tree is absolutely clean. The kernel team recommends that this command be issued prior to each kernel compilation. Do not rely on the source tree being clean after un-tarring. Configure the kernel via a menu-driven interface. Please note that the udev bootscript requires "rtc" and "tmpfs" to be enabled and built into the kernel, not as modules. CBLFS has some information regarding particular kernel configuration requirements of packages outside of CLFS at http://cblfs.cross-lfs.org/: make menuconfig Alternatively, make oldconfig may be more appropriate in some situations. See the README file for more information. If desired, skip kernel configuration by copying the kernel config file, .config, from the host system (assuming it is available) to the root directory of the unpacked kernel sources. However, we do not recommend this option. It is often better to explore all the configuration menus and create the kernel configuration from scratch. Compile the kernel image and modules: make If using kernel modules, an /etc/modprobe.conf file may be needed. Information pertaining to modules and kernel configuration is located in the kernel documentation in the Documentation directory of the kernel sources tree. Also, modprobe.conf(5) may be of interest. Be very careful when reading other documentation relating to kernel modules because it usually applies to 2.4.x kernels only. As far as we know, kernel configuration issues specific to Hotplug and Udev are not documented. The problem is that Udev will create a device node only if Hotplug or a user-written script inserts the corresponding module into the kernel, and not all modules are detectable by Hotplug. Note that statements like the one below in the /etc/modprobe.conf file do not work with Udev: alias char-major-XXX some-module Because of the complications with Udev and modules, we strongly recommend starting with a completely non-modular kernel configuration, especially if this is the first time using Udev. 222

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 Install the modules, if the kernel configuration uses them: make modules_install After kernel compilation is complete, additional steps are required to complete the installation. Some files need to be copied to the /boot directory. Issue the following command to install the kernel: cp -v arch/i386/boot/bzImage /boot/clfskernel-2.6.24.7 System.map is a symbol file for the kernel. It maps the function entry points of every function in the kernel API, as well as the addresses of the kernel data structures for the running kernel. Issue the following command to install the map file: cp -v System.map /boot/System.map-2.6.24.7 The kernel configuration file .config produced by the make menuconfig step above contains all the configuration selections for the kernel that was just compiled. It is a good idea to keep this file for future reference: cp -v .config /boot/config-2.6.24.7 It is important to note that the files in the kernel source directory are not owned by root. Whenever a package is unpacked as user root (like we do inside the final-system build environment), the files have the user and group IDs of whatever they were on the packager's computer. This is usually not a problem for any other package to be installed because the source tree is removed after the installation. However, the Linux source tree is often retained for a long time. Because of this, there is a chance that whatever user ID the packager used will be assigned to somebody on the machine. That person would then have write access to the kernel source. If the kernel source tree is going to retained, run chown -R 0:0 on the linux-2.6.24.7 directory to ensure all files are owned by user root.

Warning
Some kernel documentation recommends creating a symlink from /usr/src/linux pointing to the kernel source directory. This is specific to kernels prior to the 2.6 series and must not be created on a CLFS system as it can cause problems for packages you may wish to build once your base CLFS system is complete. Also, the headers in the system's include directory should always be the ones against which Glibc was compiled (from the Linux-Headers package) and should never be replaced by the kernel headers.

Short Descriptions
config-[linux-version] Contains all the configuration selections for the kernel clfskernel-[linux-version] The engine of the Linux system. When turning on the computer, the kernel is the first part of the operating system that gets loaded. It detects and initializes all components of the computer's hardware, then makes these 223

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 components available as a tree of files to the software and turns a single CPU into a multitasking machine capable of running scores of programs seemingly at the same time. System.map-[linux-version] A list of addresses and symbols; it maps the entry points and addresses of all the functions and data structures in the kernel

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12.4. Making the CLFS System Bootable
Your shiny new CLFS system is almost complete. One of the last things to do is to ensure that the system can be properly booted. The instructions below apply only to computers of IA-32 architecture, meaning mainstream PCs. Information on “boot loading” for other architectures should be available in the usual resource-specific locations for those architectures. Boot loading can be a complex area, so a few cautionary words are in order. Be familiar with the current boot loader and any other operating systems present on the hard drive(s) that need to be bootable. Make sure that an emergency boot disk is ready to “rescue” the computer if the computer becomes unusable (un-bootable). Earlier, we compiled and installed the GRUB boot loader software in preparation for this step. The procedure involves writing some special GRUB files to specific locations on the hard drive. We highly recommend creating a GRUB boot floppy diskette as a backup. Insert a blank floppy diskette and run the following commands: dd if=/boot/grub/stage1 of=/dev/fd0 bs=512 count=1 dd if=/boot/grub/stage2 of=/dev/fd0 bs=512 seek=1 Remove the diskette and store it somewhere safe. Now, run the grub shell: grub GRUB uses its own naming structure for drives and partitions in the form of (hdn,m), where n is the hard drive number and m is the partition number, both starting from zero. For example, partition hda1 is (hd0,0) to GRUB and hdb3 is (hd1,2). In contrast to Linux, GRUB does not consider CD-ROM drives to be hard drives. For example, if using a CD on hdb and a second hard drive on hdc, that second hard drive would still be (hd1). Using the above information, determine the appropriate designator for the root partition (or boot partition, if a separate one is used). For the following example, it is assumed that the root (or separate boot) partition is hda4. Tell GRUB where to search for its stage{1,2} files. The Tab key can be used everywhere to make GRUB show the alternatives: root (hd0,3)

Warning
The following command will overwrite the current boot loader. Do not run the command if this is not desired, for example, if using a third party boot manager to manage the Master Boot Record (MBR). In this scenario, it would make more sense to install GRUB into the “boot sector” of the CLFS partition. In this case, this next command would become setup (hd0,3). Tell GRUB to install itself into the MBR of hda: setup (hd0) If all went well, GRUB will have reported finding its files in /boot/grub. That's all there is to it. Quit the grub shell: quit 225

Chapter 13. The End
13.1. The End
Well done! The new CLFS system is installed! We wish you much success with your shiny new custom-built Linux system. It may be a good idea to create an /etc/clfs-release file. By having this file, it is very easy for you (and for us if you need to ask for help at some point) to find out which CLFS version is installed on the system. Create this file by running: echo 1.1.0 > /etc/clfs-release

13.2. Get Counted
Now that you have finished the book, do you want to be counted as a CLFS user? Head over to http://www. linuxfromscratch.org/cgi-bin/lfscounter.cgi and register as a CLFS user by entering your name and the first CLFS version you have used.

13.3. Rebooting the System
If you built your final system using the boot method, just run shutdown -r now to reboot again, using your newly-built kernel instead of the miminal one currently in use. If you chrooted, there are a few more steps. The system you have created in this book is quite minimal, and most likely will not have the functionality you would need to be able to continue forward. By installing a few extra packages from the BLFS book while still in our current chroot environment, you can leave yourself in a much better position to continue on once you reboot into your new CLFS installation. Installing a text mode web browser, such as Lynx, you can easily view the BLFS book in one virtual terminal, while building packages in another. The GPM package will also allow you to perform copy/paste actions in your virtual terminals. Lastly, if you are in a situation where static IP configuration does not meet your networking requirements, installing packages such as Dhcpcd or PPP at this point might also be useful. Now that we have said that, lets move on to booting our shiny new CLFS installation for the first time! First exit from the chroot environment: logout Then unmount the virtual file systems: umount umount umount umount umount ${CLFS}/dev/pts ${CLFS}/dev/shm ${CLFS}/dev ${CLFS}/proc ${CLFS}/sys

Unmount the CLFS file system itself: umount ${CLFS} 227

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 If multiple partitions were created, unmount the other partitions before unmounting the main one, like this: umount ${CLFS}/usr umount ${CLFS}/home umount ${CLFS} Now, reboot the system with: shutdown -r now Assuming the boot loader was set up as outlined earlier, CLFS 1.1.0 will boot automatically. When the reboot is complete, the CLFS system is ready for use and more software may be added to suit your needs.

13.4. What Now?
Thank you for reading this CLFS book. We hope that you have found this book helpful and have learned more about the system creation process. Now that the CLFS system is installed, you may be wondering “What next?” To answer that question, we have compiled a list of resources for you. • Maintenance Bugs and security notices are reported regularly for all software. Since a CLFS system is compiled from source, it is up to you to keep abreast of such reports. There are several online resources that track such reports, some of which are shown below: • Freshmeat.net (http://freshmeat.net/) Freshmeat can notify you (via email) of new versions of packages installed on your system. • CERT (Computer Emergency Response Team) CERT has a mailing list that publishes security alerts concerning various operating systems and applications. Subscription information is available at http://www.us-cert.gov/cas/signup.html. • Bugtraq Bugtraq is a full-disclosure computer security mailing list. It publishes newly discovered security issues, and occasionally potential fixes for them. Subscription information is available at http://www.securityfocus.com/ archive. • Community Driven Beyond Linux From Scratch The Community Driven Beyond Linux From Scratch wiki covers installation procedures for a wide range of software beyond the scope of the CLFS Book. CBLFS is designed specifically to work with the CLFS book, and has all the necessary information to continue the builds in the same manner that CLFS uses. This is a community driven project, which means anyone can contribute and provide updates. The CBLFS project is located at http:// cblfs.cross-lfs.org/. • CLFS Hints The CLFS Hints are a collection of educational documents submitted by volunteers in the CLFS community. The hints are available at http://hints.cross-lfs.org/. • Mailing lists 228

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 There are several CLFS mailing lists you may subscribe to if you are in need of help, want to stay current with the latest developments, want to contribute to the project, and more. See Chapter 1 - Mailing Lists for more information. • The Linux Documentation Project The goal of The Linux Documentation Project (TLDP) is to collaborate on all of the issues of Linux documentation. The TLDP features a large collection of HOWTOs, guides, and man pages. It is located at http:// www.tldp.org/.

A very special thank you to our donators
• Dean Benson <dean@vipersoft.co.uk> for several monetary contributions • Hagen Herrschaft <hrx@hrxnet.de> for donating a 2.2 GHz P4 system, now running under the name of Lorien • VA Software who, on behalf of Linux.com, donated a VA Linux 420 (former StartX SP2) workstation • Mark Stone for donating Belgarath, the linuxfromscratch.org server

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Appendix C. Dependencies
Every package built in CLFS relies on one or more other packages in order to build and install properly. Some packages even participate in circular dependencies, that is, the first package depends on the second which in turn depends on the first. Because of these dependencies, the order in which packages are built in CLFS is very important. The purpose of this page is to document the dependencies of each package built in CLFS. For each package we build, we have listed three types of dependencies. The first lists what other packages need to be available in order to compile and install the package in question. The second lists what packages, in addition to those on the first list, need to be available in order to run the testsuites. The last list of dependencies are packages that require this package to be built and installed in its final location before they are built and installed. In most cases, this is because these packages will hardcode paths to binaries within their scripts. If not built in a certain order, this could result in paths of /tools/bin/[binary] being placed inside scripts installed to the final system. This is obviously not desirable.

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Cross-Compiled Linux From Scratch - Version 1.1.0-x86 3. Acknowledgement of the original author and publisher if applicable must be retained according to normal academic citation practices. 4. The location of the original unmodified document must be identified. 5. The original author's (or authors') name(s) may not be used to assert or imply endorsement of the resulting document without the original author's (or authors') permission.

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VI. LICENSE OPTIONS
The author(s) and/or publisher of an Open Publication-licensed document may elect certain options by appending language to the reference to or copy of the license. These options are considered part of the license instance and must be included with the license (or its incorporation by reference) in derived works. A. To prohibit distribution of substantively modified versions without the explicit permission of the author(s). "Substantive modification" is defined as a change to the semantic content of the document, and excludes mere changes in format or typographical corrections. To accomplish this, add the phrase `Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder.' to the license reference or copy. B. To prohibit any publication of this work or derivative works in whole or in part in standard (paper) book form for commercial purposes is prohibited unless prior permission is obtained from the copyright holder. To accomplish this, add the phrase 'Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder.' to the license reference or copy.

OPEN PUBLICATION POLICY APPENDIX
(This is not considered part of the license.) Open Publication works are available in source format via the Open Publication home page at http://works. opencontent.org/. Open Publication authors who want to include their own license on Open Publication works may do so, as long as their terms are not more restrictive than the Open Publication license. If you have questions about the Open Publication License, please contact David Wiley at dw@opencontent.org, and/or the Open Publication Authors' List at opal@opencontent.org, via email. To subscribe to the Open Publication Authors' List: Send E-mail to opal-request@opencontent.org with the word "subscribe" in the body. 246

Cross-Compiled Linux From Scratch - Version 1.1.0-x86 To post to the Open Publication Authors' List: Send E-mail to opal@opencontent.org or simply reply to a previous post. To unsubscribe from the Open Publication Authors' List: Send E-mail to opal-request@opencontent.org with the word "unsubscribe" in the body.